| Message ID | 20171111135759.7431-1-zlang@redhat.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
On 11/11/17 7:57 AM, Zorro Lang wrote: > The 'Coverity Scan' found a problem in new write_once() function: > > 272 size_t bytes; > 273 bytes = do_pwrite(file->fd, offset, count, count, pwritev2_flags); >>>> CID 1420710: Control flow issues (NO_EFFECT) >>>> This less-than-zero comparison of an unsigned value is never true. "bytes < 0UL". > 274 if (bytes < 0) > 275 return -1; > > That's unreasonable. do_pwrite return 'ssize_t' type value, which can > be less than zero, but we use a 'size_t' to get the return value. So > change the size_t to ssize_t for it can store the return value > correctly. > > By the chance, correct all 'ssize_t' type problems in pwrite related > functions. > > Signed-off-by: Zorro Lang <zlang@redhat.com> > --- > > V2 changed more than V1, as below: > 1) The return value type of do_pwritev and do_pwrite, from 'int' to 'ssize_t' > 2) The arguments type of do_pwritev and do_pwrite, from 'ssize_t' to 'size_t' > > Thanks, > Zorro > > io/pwrite.c | 14 +++++++------- > 1 file changed, 7 insertions(+), 7 deletions(-) > > diff --git a/io/pwrite.c b/io/pwrite.c > index 26f79579..3df976a8 100644 > --- a/io/pwrite.c > +++ b/io/pwrite.c > @@ -61,12 +61,12 @@ pwrite_help(void) > } > > #ifdef HAVE_PWRITEV > -static int > +static ssize_t > do_pwritev( > int fd, > off64_t offset, > - ssize_t count, > - ssize_t buffer_size, > + size_t count, > + size_t buffer_size, I had not noticed this before, but this is odd; buffer_size is not used in this function. Instead, we test the global "buffersize" I'm not sure what's going on there, need to read the code bit more. That's probably a separate fix though. I think the rest looks ok, Reviewed-by: Eric Sandeen <sandeen@sandeen.net> > int pwritev2_flags) > { > int vecs = 0; > @@ -105,12 +105,12 @@ do_pwritev( > #define do_pwritev(fd, offset, count, buffer_size) (0) > #endif > > -static int > +static ssize_t > do_pwrite( > int fd, > off64_t offset, > - ssize_t count, > - ssize_t buffer_size, > + size_t count, > + size_t buffer_size, > int pwritev2_flags) > { > if (!vectors) > @@ -269,7 +269,7 @@ write_once( > long long *total, > int pwritev2_flags) > { > - size_t bytes; > + ssize_t bytes; > bytes = do_pwrite(file->fd, offset, count, count, pwritev2_flags); > if (bytes < 0) > return -1; > -- To unsubscribe from this list: send the line "unsubscribe linux-xfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Sat, Nov 11, 2017 at 09:46:48AM -0600, Eric Sandeen wrote: > On 11/11/17 7:57 AM, Zorro Lang wrote: > > The 'Coverity Scan' found a problem in new write_once() function: > > > > 272 size_t bytes; > > 273 bytes = do_pwrite(file->fd, offset, count, count, pwritev2_flags); > >>>> CID 1420710: Control flow issues (NO_EFFECT) > >>>> This less-than-zero comparison of an unsigned value is never true. "bytes < 0UL". > > 274 if (bytes < 0) > > 275 return -1; > > > > That's unreasonable. do_pwrite return 'ssize_t' type value, which can > > be less than zero, but we use a 'size_t' to get the return value. So > > change the size_t to ssize_t for it can store the return value > > correctly. > > > > By the chance, correct all 'ssize_t' type problems in pwrite related > > functions. > > > > Signed-off-by: Zorro Lang <zlang@redhat.com> > > --- > > > > V2 changed more than V1, as below: > > 1) The return value type of do_pwritev and do_pwrite, from 'int' to 'ssize_t' > > 2) The arguments type of do_pwritev and do_pwrite, from 'ssize_t' to 'size_t' > > > > Thanks, > > Zorro > > > > io/pwrite.c | 14 +++++++------- > > 1 file changed, 7 insertions(+), 7 deletions(-) > > > > diff --git a/io/pwrite.c b/io/pwrite.c > > index 26f79579..3df976a8 100644 > > --- a/io/pwrite.c > > +++ b/io/pwrite.c > > @@ -61,12 +61,12 @@ pwrite_help(void) > > } > > > > #ifdef HAVE_PWRITEV > > -static int > > +static ssize_t > > do_pwritev( > > int fd, > > off64_t offset, > > - ssize_t count, > > - ssize_t buffer_size, > > + size_t count, > > + size_t buffer_size, > > I had not noticed this before, but this is odd; buffer_size is not used > in this function. Instead, we test the global "buffersize" > > I'm not sure what's going on there, need to read the code bit more. > That's probably a separate fix though. The buffer_size argument in do_pwritev/do_preadv is useless. I'll remove it in a separate patch. But due to this patch changed the 'buffer_size' place, I'll send this patch and 'remove buffer_size' patch together. To prevent merge conflict. Thanks, Zorro > > I think the rest looks ok, > > Reviewed-by: Eric Sandeen <sandeen@sandeen.net> > > > > > int pwritev2_flags) > > { > > int vecs = 0; > > @@ -105,12 +105,12 @@ do_pwritev( > > #define do_pwritev(fd, offset, count, buffer_size) (0) > > #endif > > > > -static int > > +static ssize_t > > do_pwrite( > > int fd, > > off64_t offset, > > - ssize_t count, > > - ssize_t buffer_size, > > + size_t count, > > + size_t buffer_size, > > int pwritev2_flags) > > { > > if (!vectors) > > @@ -269,7 +269,7 @@ write_once( > > long long *total, > > int pwritev2_flags) > > { > > - size_t bytes; > > + ssize_t bytes; > > bytes = do_pwrite(file->fd, offset, count, count, pwritev2_flags); > > if (bytes < 0) > > return -1; > > > > -- > To unsubscribe from this list: send the line "unsubscribe linux-xfs" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-xfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/io/pwrite.c b/io/pwrite.c index 26f79579..3df976a8 100644 --- a/io/pwrite.c +++ b/io/pwrite.c @@ -61,12 +61,12 @@ pwrite_help(void) } #ifdef HAVE_PWRITEV -static int +static ssize_t do_pwritev( int fd, off64_t offset, - ssize_t count, - ssize_t buffer_size, + size_t count, + size_t buffer_size, int pwritev2_flags) { int vecs = 0; @@ -105,12 +105,12 @@ do_pwritev( #define do_pwritev(fd, offset, count, buffer_size) (0) #endif -static int +static ssize_t do_pwrite( int fd, off64_t offset, - ssize_t count, - ssize_t buffer_size, + size_t count, + size_t buffer_size, int pwritev2_flags) { if (!vectors) @@ -269,7 +269,7 @@ write_once( long long *total, int pwritev2_flags) { - size_t bytes; + ssize_t bytes; bytes = do_pwrite(file->fd, offset, count, count, pwritev2_flags); if (bytes < 0) return -1;