diff mbox series

[v14,031/138] fs/netfs: Add folio fscache functions

Message ID 20210715033704.692967-32-willy@infradead.org (mailing list archive)
State New, archived
Headers show
Series Memory folios | expand

Commit Message

Matthew Wilcox July 15, 2021, 3:35 a.m. UTC 
Match the page writeback functions by adding
folio_start_fscache(), folio_end_fscache(), folio_wait_fscache() and
folio_wait_fscache_killable().  Remove set_page_private_2().  Also rewrite
the kernel-doc to describe when to use the function rather than what the
function does, and include the kernel-doc in the appropriate rst file.
Saves 31 bytes of text in netfs_rreq_unlock() due to set_page_fscache()
calling page_folio() once instead of three times.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: William Kucharski <william.kucharski@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
---
 Documentation/filesystems/netfs_library.rst |  2 +
 include/linux/netfs.h                       | 75 +++++++++++++--------
 include/linux/pagemap.h                     | 16 -----
 3 files changed, 50 insertions(+), 43 deletions(-)

Comments

kernel test robot July 15, 2021, 9:51 a.m. UTC | #1 
Hi "Matthew,

Thank you for the patch! Yet something to improve:

[auto build test ERROR on linus/master]
[also build test ERROR on v5.14-rc1 next-20210715]
[cannot apply to hnaz-linux-mm/master xfs-linux/for-next tip/perf/core]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/Matthew-Wilcox-Oracle/Memory-folios/20210715-133101
base:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 8096acd7442e613fad0354fc8dfdb2003cceea0b
config: nios2-defconfig (attached as .config)
compiler: nios2-linux-gcc (GCC) 10.3.0
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # https://github.com/0day-ci/linux/commit/8e4044529261dffc386ab56b6d90e8511c820605
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Matthew-Wilcox-Oracle/Memory-folios/20210715-133101
        git checkout 8e4044529261dffc386ab56b6d90e8511c820605
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-10.3.0 make.cross ARCH=nios2 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All errors (new ones prefixed by >>):

   In file included from include/linux/fscache.h:22,
                    from fs/nfs/fscache.h:14,
                    from fs/nfs/client.c:48:
   include/linux/netfs.h: In function 'folio_start_fscache':
>> include/linux/netfs.h:43:2: error: implicit declaration of function 'folio_set_private_2_flag'; did you mean 'folio_set_private_2'? [-Werror=implicit-function-declaration]
      43 |  folio_set_private_2_flag(folio);
         |  ^~~~~~~~~~~~~~~~~~~~~~~~
         |  folio_set_private_2
   cc1: some warnings being treated as errors


vim +43 include/linux/netfs.h

    31	
    32	/**
    33	 * folio_start_fscache - Start an fscache write on a folio.
    34	 * @folio: The folio.
    35	 *
    36	 * Call this function before writing a folio to a local cache.  Starting a
    37	 * second write before the first one finishes is not allowed.
    38	 */
    39	static inline void folio_start_fscache(struct folio *folio)
    40	{
    41		VM_BUG_ON_FOLIO(folio_test_private_2(folio), folio);
    42		folio_get(folio);
  > 43		folio_set_private_2_flag(folio);
    44	}
    45	

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org
kernel test robot July 15, 2021, 10:33 a.m. UTC | #2 
Hi "Matthew,

Thank you for the patch! Yet something to improve:

[auto build test ERROR on linus/master]
[also build test ERROR on v5.14-rc1 next-20210715]
[cannot apply to hnaz-linux-mm/master xfs-linux/for-next tip/perf/core]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/Matthew-Wilcox-Oracle/Memory-folios/20210715-133101
base:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 8096acd7442e613fad0354fc8dfdb2003cceea0b
config: powerpc-randconfig-r033-20210715 (attached as .config)
compiler: clang version 13.0.0 (https://github.com/llvm/llvm-project 0e49c54a8cbd3e779e5526a5888c683c01cc3c50)
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # install powerpc cross compiling tool for clang build
        # apt-get install binutils-powerpc-linux-gnu
        # https://github.com/0day-ci/linux/commit/8e4044529261dffc386ab56b6d90e8511c820605
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Matthew-Wilcox-Oracle/Memory-folios/20210715-133101
        git checkout 8e4044529261dffc386ab56b6d90e8511c820605
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=powerpc 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All errors (new ones prefixed by >>):

   In file included from include/linux/pagemap.h:11:
   In file included from include/linux/highmem.h:10:
   In file included from include/linux/hardirq.h:11:
   In file included from arch/powerpc/include/asm/hardirq.h:6:
   In file included from include/linux/irq.h:20:
   In file included from include/linux/io.h:13:
   In file included from arch/powerpc/include/asm/io.h:619:
   arch/powerpc/include/asm/io-defs.h:45:1: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
   DEF_PCI_AC_NORET(insw, (unsigned long p, void *b, unsigned long c),
   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   arch/powerpc/include/asm/io.h:616:3: note: expanded from macro 'DEF_PCI_AC_NORET'
                   __do_##name al;                                 \
                   ^~~~~~~~~~~~~~
   <scratch space>:16:1: note: expanded from here
   __do_insw
   ^
   arch/powerpc/include/asm/io.h:557:56: note: expanded from macro '__do_insw'
   #define __do_insw(p, b, n)      readsw((PCI_IO_ADDR)_IO_BASE+(p), (b), (n))
                                          ~~~~~~~~~~~~~~~~~~~~~^
   In file included from fs/netfs/read_helper.c:12:
   In file included from include/linux/pagemap.h:11:
   In file included from include/linux/highmem.h:10:
   In file included from include/linux/hardirq.h:11:
   In file included from arch/powerpc/include/asm/hardirq.h:6:
   In file included from include/linux/irq.h:20:
   In file included from include/linux/io.h:13:
   In file included from arch/powerpc/include/asm/io.h:619:
   arch/powerpc/include/asm/io-defs.h:47:1: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
   DEF_PCI_AC_NORET(insl, (unsigned long p, void *b, unsigned long c),
   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   arch/powerpc/include/asm/io.h:616:3: note: expanded from macro 'DEF_PCI_AC_NORET'
                   __do_##name al;                                 \
                   ^~~~~~~~~~~~~~
   <scratch space>:20:1: note: expanded from here
   __do_insl
   ^
   arch/powerpc/include/asm/io.h:558:56: note: expanded from macro '__do_insl'
   #define __do_insl(p, b, n)      readsl((PCI_IO_ADDR)_IO_BASE+(p), (b), (n))
                                          ~~~~~~~~~~~~~~~~~~~~~^
   In file included from fs/netfs/read_helper.c:12:
   In file included from include/linux/pagemap.h:11:
   In file included from include/linux/highmem.h:10:
   In file included from include/linux/hardirq.h:11:
   In file included from arch/powerpc/include/asm/hardirq.h:6:
   In file included from include/linux/irq.h:20:
   In file included from include/linux/io.h:13:
   In file included from arch/powerpc/include/asm/io.h:619:
   arch/powerpc/include/asm/io-defs.h:49:1: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
   DEF_PCI_AC_NORET(outsb, (unsigned long p, const void *b, unsigned long c),
   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   arch/powerpc/include/asm/io.h:616:3: note: expanded from macro 'DEF_PCI_AC_NORET'
                   __do_##name al;                                 \
                   ^~~~~~~~~~~~~~
   <scratch space>:24:1: note: expanded from here
   __do_outsb
   ^
   arch/powerpc/include/asm/io.h:559:58: note: expanded from macro '__do_outsb'
   #define __do_outsb(p, b, n)     writesb((PCI_IO_ADDR)_IO_BASE+(p),(b),(n))
                                           ~~~~~~~~~~~~~~~~~~~~~^
   In file included from fs/netfs/read_helper.c:12:
   In file included from include/linux/pagemap.h:11:
   In file included from include/linux/highmem.h:10:
   In file included from include/linux/hardirq.h:11:
   In file included from arch/powerpc/include/asm/hardirq.h:6:
   In file included from include/linux/irq.h:20:
   In file included from include/linux/io.h:13:
   In file included from arch/powerpc/include/asm/io.h:619:
   arch/powerpc/include/asm/io-defs.h:51:1: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
   DEF_PCI_AC_NORET(outsw, (unsigned long p, const void *b, unsigned long c),
   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   arch/powerpc/include/asm/io.h:616:3: note: expanded from macro 'DEF_PCI_AC_NORET'
                   __do_##name al;                                 \
                   ^~~~~~~~~~~~~~
   <scratch space>:28:1: note: expanded from here
   __do_outsw
   ^
   arch/powerpc/include/asm/io.h:560:58: note: expanded from macro '__do_outsw'
   #define __do_outsw(p, b, n)     writesw((PCI_IO_ADDR)_IO_BASE+(p),(b),(n))
                                           ~~~~~~~~~~~~~~~~~~~~~^
   In file included from fs/netfs/read_helper.c:12:
   In file included from include/linux/pagemap.h:11:
   In file included from include/linux/highmem.h:10:
   In file included from include/linux/hardirq.h:11:
   In file included from arch/powerpc/include/asm/hardirq.h:6:
   In file included from include/linux/irq.h:20:
   In file included from include/linux/io.h:13:
   In file included from arch/powerpc/include/asm/io.h:619:
   arch/powerpc/include/asm/io-defs.h:53:1: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
   DEF_PCI_AC_NORET(outsl, (unsigned long p, const void *b, unsigned long c),
   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   arch/powerpc/include/asm/io.h:616:3: note: expanded from macro 'DEF_PCI_AC_NORET'
                   __do_##name al;                                 \
                   ^~~~~~~~~~~~~~
   <scratch space>:32:1: note: expanded from here
   __do_outsl
   ^
   arch/powerpc/include/asm/io.h:561:58: note: expanded from macro '__do_outsl'
   #define __do_outsl(p, b, n)     writesl((PCI_IO_ADDR)_IO_BASE+(p),(b),(n))
                                           ~~~~~~~~~~~~~~~~~~~~~^
   In file included from fs/netfs/read_helper.c:17:
>> include/linux/netfs.h:43:2: error: implicit declaration of function 'folio_set_private_2_flag' [-Werror,-Wimplicit-function-declaration]
           folio_set_private_2_flag(folio);
           ^
   include/linux/netfs.h:43:2: note: did you mean 'folio_set_private_2'?
   include/linux/page-flags.h:445:1: note: 'folio_set_private_2' declared here
   PAGEFLAG(Private2, private_2, PF_ANY) TESTSCFLAG(Private2, private_2, PF_ANY)
   ^
   include/linux/page-flags.h:362:2: note: expanded from macro 'PAGEFLAG'
           SETPAGEFLAG(uname, lname, policy)                               \
           ^
   include/linux/page-flags.h:320:6: note: expanded from macro 'SETPAGEFLAG'
   void folio_set_##lname(struct folio *folio)                             \
        ^
   <scratch space>:70:1: note: expanded from here
   folio_set_private_2
   ^
   12 warnings and 1 error generated.


vim +/folio_set_private_2_flag +43 include/linux/netfs.h

    31	
    32	/**
    33	 * folio_start_fscache - Start an fscache write on a folio.
    34	 * @folio: The folio.
    35	 *
    36	 * Call this function before writing a folio to a local cache.  Starting a
    37	 * second write before the first one finishes is not allowed.
    38	 */
    39	static inline void folio_start_fscache(struct folio *folio)
    40	{
    41		VM_BUG_ON_FOLIO(folio_test_private_2(folio), folio);
    42		folio_get(folio);
  > 43		folio_set_private_2_flag(folio);
    44	}
    45	

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org
Matthew Wilcox July 15, 2021, 11:15 a.m. UTC | #3 
On Thu, Jul 15, 2021 at 05:51:26PM +0800, kernel test robot wrote:
>    include/linux/netfs.h: In function 'folio_start_fscache':
> >> include/linux/netfs.h:43:2: error: implicit declaration of function 'folio_set_private_2_flag'; did you mean 'folio_set_private_2'? [-Werror=implicit-function-declaration]
>       43 |  folio_set_private_2_flag(folio);
>          |  ^~~~~~~~~~~~~~~~~~~~~~~~
>          |  folio_set_private_2
>    cc1: some warnings being treated as errors

I'll be folding in this patch:

+++ b/include/linux/netfs.h
@@ -40,7 +40,7 @@ static inline void folio_start_fscache(struct folio *folio)
 {
        VM_BUG_ON_FOLIO(folio_test_private_2(folio), folio);
        folio_get(folio);
-       folio_set_private_2_flag(folio);
+       folio_set_private_2(folio);
 }

 /**
Mike Rapoport July 21, 2021, 9:44 a.m. UTC | #4 
On Thu, Jul 15, 2021 at 04:35:17AM +0100, Matthew Wilcox (Oracle) wrote:
> Match the page writeback functions by adding
> folio_start_fscache(), folio_end_fscache(), folio_wait_fscache() and
> folio_wait_fscache_killable().  Remove set_page_private_2().  Also rewrite
> the kernel-doc to describe when to use the function rather than what the
> function does, and include the kernel-doc in the appropriate rst file.
> Saves 31 bytes of text in netfs_rreq_unlock() due to set_page_fscache()
> calling page_folio() once instead of three times.
> 
> Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
> Acked-by: Vlastimil Babka <vbabka@suse.cz>
> Reviewed-by: William Kucharski <william.kucharski@oracle.com>
> Reviewed-by: Christoph Hellwig <hch@lst.de>
> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
> ---
>  Documentation/filesystems/netfs_library.rst |  2 +
>  include/linux/netfs.h                       | 75 +++++++++++++--------
>  include/linux/pagemap.h                     | 16 -----
>  3 files changed, 50 insertions(+), 43 deletions(-)

Acked-by: Mike Rapoport <rppt@linux.ibm.com>
David Howells Aug. 10, 2021, 3:39 p.m. UTC | #5 
Matthew Wilcox (Oracle) <willy@infradead.org> wrote:

> Match the page writeback functions by adding
> folio_start_fscache(), folio_end_fscache(), folio_wait_fscache() and
> folio_wait_fscache_killable().  Remove set_page_private_2().  Also rewrite
> the kernel-doc to describe when to use the function rather than what the
> function does, and include the kernel-doc in the appropriate rst file.
> Saves 31 bytes of text in netfs_rreq_unlock() due to set_page_fscache()
> calling page_folio() once instead of three times.
> 
> Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
> Acked-by: Vlastimil Babka <vbabka@suse.cz>
> Reviewed-by: William Kucharski <william.kucharski@oracle.com>
> Reviewed-by: Christoph Hellwig <hch@lst.de>
> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>

Assuming you fixed the kernel test robot report:

Reviewed-by: David Howells <dhowells@redhat.com>
diff mbox series

Patch

diff --git a/Documentation/filesystems/netfs_library.rst b/Documentation/filesystems/netfs_library.rst
index 57a641847818..bb68d39f03b7 100644
--- a/Documentation/filesystems/netfs_library.rst
+++ b/Documentation/filesystems/netfs_library.rst
@@ -524,3 +524,5 @@  Note that these methods are passed a pointer to the cache resource structure,
 not the read request structure as they could be used in other situations where
 there isn't a read request structure as well, such as writing dirty data to the
 cache.
+
+.. kernel-doc:: include/linux/netfs.h
diff --git a/include/linux/netfs.h b/include/linux/netfs.h
index fad8c6209edd..e03ed7fc3aef 100644
--- a/include/linux/netfs.h
+++ b/include/linux/netfs.h
@@ -22,6 +22,7 @@ 
  * Overload PG_private_2 to give us PG_fscache - this is used to indicate that
  * a page is currently backed by a local disk cache
  */
+#define folio_test_fscache(folio)	folio_test_private_2(folio)
 #define PageFsCache(page)		PagePrivate2((page))
 #define SetPageFsCache(page)		SetPagePrivate2((page))
 #define ClearPageFsCache(page)		ClearPagePrivate2((page))
@@ -29,57 +30,77 @@ 
 #define TestClearPageFsCache(page)	TestClearPagePrivate2((page))
 
 /**
- * set_page_fscache - Set PG_fscache on a page and take a ref
- * @page: The page.
+ * folio_start_fscache - Start an fscache write on a folio.
+ * @folio: The folio.
  *
- * Set the PG_fscache (PG_private_2) flag on a page and take the reference
- * needed for the VM to handle its lifetime correctly.  This sets the flag and
- * takes the reference unconditionally, so care must be taken not to set the
- * flag again if it's already set.
+ * Call this function before writing a folio to a local cache.  Starting a
+ * second write before the first one finishes is not allowed.
  */
-static inline void set_page_fscache(struct page *page)
+static inline void folio_start_fscache(struct folio *folio)
 {
-	set_page_private_2(page);
+	VM_BUG_ON_FOLIO(folio_test_private_2(folio), folio);
+	folio_get(folio);
+	folio_set_private_2_flag(folio);
 }
 
 /**
- * end_page_fscache - Clear PG_fscache and release any waiters
- * @page: The page
- *
- * Clear the PG_fscache (PG_private_2) bit on a page and wake up any sleepers
- * waiting for this.  The page ref held for PG_private_2 being set is released.
+ * folio_end_fscache - End an fscache write on a folio.
+ * @folio: The folio.
  *
- * This is, for example, used when a netfs page is being written to a local
- * disk cache, thereby allowing writes to the cache for the same page to be
- * serialised.
+ * Call this function after the folio has been written to the local cache.
+ * This will wake any sleepers waiting on this folio.
  */
-static inline void end_page_fscache(struct page *page)
+static inline void folio_end_fscache(struct folio *folio)
 {
-	folio_end_private_2(page_folio(page));
+	folio_end_private_2(folio);
 }
 
 /**
- * wait_on_page_fscache - Wait for PG_fscache to be cleared on a page
- * @page: The page to wait on
+ * folio_wait_fscache - Wait for an fscache write on this folio to end.
+ * @folio: The folio.
  *
- * Wait for PG_fscache (aka PG_private_2) to be cleared on a page.
+ * If this folio is currently being written to a local cache, wait for
+ * the write to finish.  Another write may start after this one finishes,
+ * unless the caller holds the folio lock.
  */
-static inline void wait_on_page_fscache(struct page *page)
+static inline void folio_wait_fscache(struct folio *folio)
 {
-	folio_wait_private_2(page_folio(page));
+	folio_wait_private_2(folio);
 }
 
 /**
- * wait_on_page_fscache_killable - Wait for PG_fscache to be cleared on a page
- * @page: The page to wait on
+ * folio_wait_fscache_killable - Wait for an fscache write on this folio to end.
+ * @folio: The folio.
  *
- * Wait for PG_fscache (aka PG_private_2) to be cleared on a page or until a
- * fatal signal is received by the calling task.
+ * If this folio is currently being written to a local cache, wait
+ * for the write to finish or for a fatal signal to be received.
+ * Another write may start after this one finishes, unless the caller
+ * holds the folio lock.
  *
  * Return:
  * - 0 if successful.
  * - -EINTR if a fatal signal was encountered.
  */
+static inline int folio_wait_fscache_killable(struct folio *folio)
+{
+	return folio_wait_private_2_killable(folio);
+}
+
+static inline void set_page_fscache(struct page *page)
+{
+	folio_start_fscache(page_folio(page));
+}
+
+static inline void end_page_fscache(struct page *page)
+{
+	folio_end_private_2(page_folio(page));
+}
+
+static inline void wait_on_page_fscache(struct page *page)
+{
+	folio_wait_private_2(page_folio(page));
+}
+
 static inline int wait_on_page_fscache_killable(struct page *page)
 {
 	return folio_wait_private_2_killable(page_folio(page));
diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index edf58a581bce..08f40e004d97 100644
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -780,22 +780,6 @@  int __set_page_dirty_no_writeback(struct page *page);
 
 void page_endio(struct page *page, bool is_write, int err);
 
-/**
- * set_page_private_2 - Set PG_private_2 on a page and take a ref
- * @page: The page.
- *
- * Set the PG_private_2 flag on a page and take the reference needed for the VM
- * to handle its lifetime correctly.  This sets the flag and takes the
- * reference unconditionally, so care must be taken not to set the flag again
- * if it's already set.
- */
-static inline void set_page_private_2(struct page *page)
-{
-	page = compound_head(page);
-	get_page(page);
-	SetPagePrivate2(page);
-}
-
 void folio_end_private_2(struct folio *folio);
 void folio_wait_private_2(struct folio *folio);
 int folio_wait_private_2_killable(struct folio *folio);