pagemap: return EINVAL, not EIO, for unaligned reads of kpagecount or kpageflags

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 <ttuttle@google.com>
Cc: Matt Mackall <mpm@selenic.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/fs/proc/proc_misc.c b/fs/proc/proc_misc.c
index 5a16090a6d6e270086bf136f84aaf14b0f8ddb26..7e277f2ad466da31d9233a06f17963c718c37397 100644 (file)
--- 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;