[PATCH 3/4] pagemap: Return EINVAL, not EIO, for unaligned reads of kpagecount or kpageflags (v2 of series)

[PATCH 3/4] pagemap: Return EINVAL, not EIO, for unaligned reads of kpagecount or kpageflags (v2 of series)

[Thomas Tuttle]

If the user tries to read from a position that is not a multiple of 8, or
read a number of bytes that is not a multiple of 8, they have passed an
invalid argument to read, for the purpose of reading these files.  It's
not an IO error because we didn't encounter any trouble finding the data
they asked for.

Signed-off-by: Thomas Tuttle
---
 fs/proc/proc_misc.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/fs/proc/proc_misc.c b/fs/proc/proc_misc.c
index 5a16090..7e277f2 100644
--- a/fs/proc/proc_misc.c
+++ b/fs/proc/proc_misc.c
@@ -716,7 +716,7 @@ static ssize_t kpagecount_read(struct file *file,
char __user *buf,
        pfn = src / KPMSIZE;
        count = min_t(size_t, count, (max_pfn * KPMSIZE) - src);
        if (src & KPMMASK || count & KPMMASK)
-               return -EIO;
+               return -EINVAL;

        while (count > 0) {
                ppage = NULL;
@@ -782,7 +782,7 @@ static ssize_t kpageflags_read(struct file *file,
char __user *buf,
        pfn = src / KPMSIZE;
        count = min_t(unsigned long, count, (max_pfn * KPMSIZE) - src);
        if (src & KPMMASK || count & KPMMASK)
-               return -EIO;
+               return -EINVAL;

        while (count > 0) {
                ppage = NULL;
--
1.5.3.6

Re: [PATCH 3/4] pagemap: Return EINVAL, not EIO, for unaligned reads of kpagecount or kpageflags (v2 of series)

[Matt Mackall]

On Thu, 2008-06-05 at 14:40 -0400, Thomas Tuttle wrote:
> If the user tries to read from a position that is not a multiple of 8, or
> read a number of bytes that is not a multiple of 8, they have passed an
> invalid argument to read, for the purpose of reading these files.  It's
> not an IO error because we didn't encounter any trouble finding the data
> they asked for.

Hmm. I seem to recall choosing EIO because that's what unaligned reads
with direct I/O report. I don't particularly care though.

Acked-by: Matt Mackall <mpm@selenic.com>

-- 
Mathematics is the supreme nostalgia of our time.