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[209.85.220.65]) by mx.google.com with SMTPS id l36-v6sor14784326plg.12.2018.11.02.22.01.35 for (Google Transport Security); Fri, 02 Nov 2018 22:01:36 -0700 (PDT) Received-SPF: pass (google.com: domain of jrdr.linux@gmail.com designates 209.85.220.65 as permitted sender) client-ip=209.85.220.65; Authentication-Results: mx.google.com; dkim=pass header.i=@gmail.com header.s=20161025 header.b="V2/j/FON"; spf=pass (google.com: domain of jrdr.linux@gmail.com designates 209.85.220.65 as permitted sender) smtp.mailfrom=jrdr.linux@gmail.com; dmarc=pass (p=NONE sp=QUARANTINE dis=NONE) header.from=gmail.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:mime-version:content-disposition :user-agent; bh=H6vjzSYHdXeMDhN+Rwiu5OZOuRwTYFnzFfoeMp5ZVu0=; b=V2/j/FON7g7g8rwYTp+rxe4af/2+w41SZkQC82sI2r36WlNafvqB3plQB/qYVFUSfp i9Ql0NfnTNYeuSACEeo90UrLyue4/osRorK6rphqt81QRNb69vxPiW5IcTELB1Z9Yseb 7XBvBtPxmKUx3CTLJmUI5evLM1aoSInXpS6qpBPgoFp4j6724UsTQRVZC14vVKYpw3L2 88GRXsuuY/9cv8DD4VLa4QUe+Y8+016R/YbDaflv21PeJ5RZ3TAFGPIQUcg8T5Lfdnbc K8UiXRUT2Y+4cKVU5L+FiICJjyymCLzeBLp55RMFd/s4ZuMaW5ttYCn0rGB218IF6FrA rD7w== X-Google-Smtp-Source: AJdET5cJSg7DnsEpjwNIX3BfHj19NlARK9ChbngQfoPpsUkhBgmYyK8ra0XxE6saAT/Iv2G1mjyTug== X-Received: by 2002:a17:902:2bc3:: with SMTP id l61-v6mr9232881plb.5.1541221295493; Fri, 02 Nov 2018 22:01:35 -0700 (PDT) Received: from jordon-HP-15-Notebook-PC ([103.227.99.32]) by smtp.gmail.com with ESMTPSA id b75-v6sm1423851pfb.96.2018.11.02.22.01.33 (version=TLS1 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Fri, 02 Nov 2018 22:01:33 -0700 (PDT) Date: Sat, 3 Nov 2018 10:35:04 +0530 From: Souptick Joarder To: willy@infradead.org, akpm@linux-foundation.org, mhocko@suse.com, dan.j.williams@intel.com, kirill.shutemov@linux.intel.com, pasha.tatashin@oracle.com, vbabka@suse.cz, riel@redhat.com Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: [PATCH] mm: Create the new vm_fault_t type Message-ID: <20181103050504.GA3049@jordon-HP-15-Notebook-PC> MIME-Version: 1.0 Content-Disposition: inline User-Agent: Mutt/1.5.21 (2010-09-15) X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: X-Virus-Scanned: ClamAV using ClamSMTP Page fault handlers are supposed to return VM_FAULT codes, but some drivers/file systems mistakenly return error numbers. Now that all drivers/file systems have been converted to use the vm_fault_t return type, change the type definition to no longer be compatible with 'int'. By making it an unsigned int, the function prototype becomes incompatible with a function which returns int. Sparse will detect any attempts to return a value which is not a VM_FAULT code. Signed-off-by: Souptick Joarder --- include/linux/mm.h | 46 ----------------------------- include/linux/mm_types.h | 75 +++++++++++++++++++++++++++++++++++++++++++++++- 2 files changed, 74 insertions(+), 47 deletions(-) diff --git a/include/linux/mm.h b/include/linux/mm.h index fcf9cc9..511a3ce 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -1267,52 +1267,6 @@ static inline void clear_page_pfmemalloc(struct page *page) } /* - * Different kinds of faults, as returned by handle_mm_fault(). - * Used to decide whether a process gets delivered SIGBUS or - * just gets major/minor fault counters bumped up. - */ - -#define VM_FAULT_OOM 0x0001 -#define VM_FAULT_SIGBUS 0x0002 -#define VM_FAULT_MAJOR 0x0004 -#define VM_FAULT_WRITE 0x0008 /* Special case for get_user_pages */ -#define VM_FAULT_HWPOISON 0x0010 /* Hit poisoned small page */ -#define VM_FAULT_HWPOISON_LARGE 0x0020 /* Hit poisoned large page. Index encoded in upper bits */ -#define VM_FAULT_SIGSEGV 0x0040 - -#define VM_FAULT_NOPAGE 0x0100 /* ->fault installed the pte, not return page */ -#define VM_FAULT_LOCKED 0x0200 /* ->fault locked the returned page */ -#define VM_FAULT_RETRY 0x0400 /* ->fault blocked, must retry */ -#define VM_FAULT_FALLBACK 0x0800 /* huge page fault failed, fall back to small */ -#define VM_FAULT_DONE_COW 0x1000 /* ->fault has fully handled COW */ -#define VM_FAULT_NEEDDSYNC 0x2000 /* ->fault did not modify page tables - * and needs fsync() to complete (for - * synchronous page faults in DAX) */ - -#define VM_FAULT_ERROR (VM_FAULT_OOM | VM_FAULT_SIGBUS | VM_FAULT_SIGSEGV | \ - VM_FAULT_HWPOISON | VM_FAULT_HWPOISON_LARGE | \ - VM_FAULT_FALLBACK) - -#define VM_FAULT_RESULT_TRACE \ - { VM_FAULT_OOM, "OOM" }, \ - { VM_FAULT_SIGBUS, "SIGBUS" }, \ - { VM_FAULT_MAJOR, "MAJOR" }, \ - { VM_FAULT_WRITE, "WRITE" }, \ - { VM_FAULT_HWPOISON, "HWPOISON" }, \ - { VM_FAULT_HWPOISON_LARGE, "HWPOISON_LARGE" }, \ - { VM_FAULT_SIGSEGV, "SIGSEGV" }, \ - { VM_FAULT_NOPAGE, "NOPAGE" }, \ - { VM_FAULT_LOCKED, "LOCKED" }, \ - { VM_FAULT_RETRY, "RETRY" }, \ - { VM_FAULT_FALLBACK, "FALLBACK" }, \ - { VM_FAULT_DONE_COW, "DONE_COW" }, \ - { VM_FAULT_NEEDDSYNC, "NEEDDSYNC" } - -/* Encode hstate index for a hwpoisoned large page */ -#define VM_FAULT_SET_HINDEX(x) ((x) << 12) -#define VM_FAULT_GET_HINDEX(x) (((x) >> 12) & 0xf) - -/* * Can be called by the pagefault handler when it gets a VM_FAULT_OOM. */ extern void pagefault_out_of_memory(void); diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h index 5ed8f62..48c2108 100644 --- a/include/linux/mm_types.h +++ b/include/linux/mm_types.h @@ -22,7 +22,6 @@ #endif #define AT_VECTOR_SIZE (2*(AT_VECTOR_SIZE_ARCH + AT_VECTOR_SIZE_BASE + 1)) -typedef int vm_fault_t; struct address_space; struct mem_cgroup; @@ -609,6 +608,80 @@ static inline bool mm_tlb_flush_nested(struct mm_struct *mm) struct vm_fault; +/** + * typedef vm_fault_t - __bitwise unsigned int + * + * vm_fault_t is the new unsigned int type to return VM_FAULT + * code by page fault handlers of drivers/file systems. Now if + * any page fault handlers returns non VM_FAULT code instead + * of VM_FAULT code, it will be a mismatch with function + * prototype and sparse will detect it. + */ +typedef __bitwise unsigned int vm_fault_t; + +/** + * enum - VM_FAULT code + * + * This enum is used to track the VM_FAULT code return by page + * fault handlers. + * + * @VM_FAULT_OOM: Out Of Memory + * @VM_FAULT_SIGBUS: Bad access + * @VM_FAULT_MAJOR: Page read from storage + * @VM_FAULT_WRITE: Special case for get_user_pages + * @VM_FAULT_HWPOISON: Hit poisoned small page + * @VM_FAULT_HWPOISON_LARGE: Hit poisoned large page. Index encoded + * in upper bits + * @VM_FAULT_SIGSEGV: segmentation fault + * @VM_FAULT_NOPAGE: ->fault installed the pte, not return page + * @VM_FAULT_LOCKED: ->fault locked the returned page + * @VM_FAULT_RETRY: ->fault blocked, must retry + * @VM_FAULT_FALLBACK: huge page fault failed, fall back to small + * @VM_FAULT_DONE_COW: ->fault has fully handled COW + * @VM_FAULT_NEEDDSYNC: ->fault did not modify page tables and needs + * fsync() to complete (for synchronous page faults + * in DAX) + */ +enum { + VM_FAULT_OOM = (__force vm_fault_t)0x000001, + VM_FAULT_SIGBUS = (__force vm_fault_t)0x000002, + VM_FAULT_MAJOR = (__force vm_fault_t)0x000004, + VM_FAULT_WRITE = (__force vm_fault_t)0x000008, + VM_FAULT_HWPOISON = (__force vm_fault_t)0x000010, + VM_FAULT_HWPOISON_LARGE = (__force vm_fault_t)0x000020, + VM_FAULT_SIGSEGV = (__force vm_fault_t)0x000040, + VM_FAULT_NOPAGE = (__force vm_fault_t)0x000100, + VM_FAULT_LOCKED = (__force vm_fault_t)0x000200, + VM_FAULT_RETRY = (__force vm_fault_t)0x000400, + VM_FAULT_FALLBACK = (__force vm_fault_t)0x000800, + VM_FAULT_DONE_COW = (__force vm_fault_t)0x001000, + VM_FAULT_NEEDDSYNC = (__force vm_fault_t)0x002000, + VM_FAULT_HINDEX_MASK = (__force vm_fault_t)0x0f0000, +}; + +/* Encode hstate index for a hwpoisoned large page */ +#define VM_FAULT_SET_HINDEX(x) ((__force vm_fault_t)((x) << 16)) +#define VM_FAULT_GET_HINDEX(x) (((x) >> 16) & 0xf) + +#define VM_FAULT_ERROR (VM_FAULT_OOM | VM_FAULT_SIGBUS | \ + VM_FAULT_SIGSEGV | VM_FAULT_HWPOISON | \ + VM_FAULT_HWPOISON_LARGE | VM_FAULT_FALLBACK) + +#define VM_FAULT_RESULT_TRACE \ + { VM_FAULT_OOM, "OOM" }, \ + { VM_FAULT_SIGBUS, "SIGBUS" }, \ + { VM_FAULT_MAJOR, "MAJOR" }, \ + { VM_FAULT_WRITE, "WRITE" }, \ + { VM_FAULT_HWPOISON, "HWPOISON" }, \ + { VM_FAULT_HWPOISON_LARGE, "HWPOISON_LARGE" }, \ + { VM_FAULT_SIGSEGV, "SIGSEGV" }, \ + { VM_FAULT_NOPAGE, "NOPAGE" }, \ + { VM_FAULT_LOCKED, "LOCKED" }, \ + { VM_FAULT_RETRY, "RETRY" }, \ + { VM_FAULT_FALLBACK, "FALLBACK" }, \ + { VM_FAULT_DONE_COW, "DONE_COW" }, \ + { VM_FAULT_NEEDDSYNC, "NEEDDSYNC" } + struct vm_special_mapping { const char *name; /* The name, e.g. "[vdso]". */