From: "Steven Rostedt (VMware)" <rostedt@xxxxxxxxxxx> Subject: mm/shmem.c: fix unlikely() test of info->seals to test only for WRITE and GROW Running my likely/unlikely profiler, I discovered that the test in shmem_write_begin() that tests for info->seals as unlikely, is always incorrect. This is because shmem_get_inode() sets info->seals to have F_SEAL_SEAL set by default, and it is unlikely to be cleared when shmem_write_begin() is called. Thus, the if statement is very likely. But as the if statement block only cares about F_SEAL_WRITE and F_SEAL_GROW, change the test to only test those two bits. Link: http://lkml.kernel.org/r/20170203105656.7aec6237@xxxxxxxxxxxxxxxxxx Signed-off-by: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx> Acked-by: Hugh Dickins <hughd@xxxxxxxxxx> Cc: David Herrmann <dh.herrmann@xxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/shmem.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff -puN mm/shmem.c~shm-fix-unlikely-test-of-info-seals-to-test-only-for-write-and-grow mm/shmem.c --- a/mm/shmem.c~shm-fix-unlikely-test-of-info-seals-to-test-only-for-write-and-grow +++ a/mm/shmem.c @@ -2331,7 +2331,7 @@ shmem_write_begin(struct file *file, str pgoff_t index = pos >> PAGE_SHIFT; /* i_mutex is held by caller */ - if (unlikely(info->seals)) { + if (unlikely(info->seals & (F_SEAL_WRITE | F_SEAL_GROW))) { if (info->seals & F_SEAL_WRITE) return -EPERM; if ((info->seals & F_SEAL_GROW) && pos + len > inode->i_size) _ -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
