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authorAl Viro <viro@zeniv.linux.org.uk>2015-03-31 11:54:59 -0400
committerAl Viro <viro@zeniv.linux.org.uk>2015-04-11 22:27:55 -0400
commit47e393622bbdd48aa21837eb2c55ee1c359e080c (patch)
tree603da19bd5834a44723bd39693373ec56ca1e75d /fs/aio.c
parent08397acdd0f02d566154c9ac7f625ae8e77133b3 (diff)
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aio_run_iocb(): kill dead check
We check if ->ki_pos is positive. However, by that point we have already done rw_verify_area(), which would have rejected such unless the file had been one of /dev/mem, /dev/kmem and /proc/kcore. All of which do not have vectored rw methods, so we would've bailed out even earlier. This check had been introduced before rw_verify_area() had been added there - in fact, it was a subset of checks done on sync paths by rw_verify_area() (back then the /dev/mem exception didn't exist at all). The rest of checks (mandatory locking, etc.) hadn't been added until later. Unfortunately, by the time the call of rw_verify_area() got added, the /dev/mem exception had already appeared, so it wasn't obvious that the older explicit check downstream had become dead code. It *is* a dead code, though, since the few files for which the exception applies do not have ->aio_{read,write}() or ->{read,write}_iter() and for them we won't reach that check anyway. What's more, even if we ever introduce vectored methods for /dev/mem and friends, they'll have to cope with negative positions anyway, since readv(2) and writev(2) are using the same checks as read(2) and write(2) - i.e. rw_verify_area(). Let's bury it. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'fs/aio.c')
-rw-r--r--fs/aio.c7
1 files changed, 0 insertions, 7 deletions
diff --git a/fs/aio.c b/fs/aio.c
index 40fddf4217bd..f0b0a2f8a63f 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -1422,13 +1422,6 @@ rw_common:
len = ret;
- /* XXX: move/kill - rw_verify_area()? */
- /* This matches the pread()/pwrite() logic */
- if (req->ki_pos < 0) {
- ret = -EINVAL;
- break;
- }
-
if (rw == WRITE)
file_start_write(file);