diff options
| author | Kirill A. Shutemov <kirill.shutemov@linux.intel.com> | 2023-03-15 14:31:26 +0300 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2023-04-05 19:42:45 -0700 |
| commit | 5f29298fba1ad1e7139381e19e09c272db337b13 (patch) | |
| tree | 5b0becdbd5ed4369b79f218ddeeb55f5d0c7b0bf /drivers/block/floppy.c | |
| parent | 254ca6d261d4b6ce00591de110f6f96c3556dfbe (diff) | |
| download | lwn-5f29298fba1ad1e7139381e19e09c272db337b13.tar.gz lwn-5f29298fba1ad1e7139381e19e09c272db337b13.zip | |
floppy: fix MAX_ORDER usage
MAX_ORDER is not inclusive: the maximum allocation order buddy allocator
can deliver is MAX_ORDER-1.
Fix MAX_ORDER usage in floppy code.
Also allocation buffer exactly PAGE_SIZE << MAX_ORDER bytes is okay. Fix
MAX_LEN check.
Link: https://lkml.kernel.org/r/20230315113133.11326-4-kirill.shutemov@linux.intel.com
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Denis Efremov <efremov@linux.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'drivers/block/floppy.c')
| -rw-r--r-- | drivers/block/floppy.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/drivers/block/floppy.c b/drivers/block/floppy.c index 487840e3564d..90d2dfb6448e 100644 --- a/drivers/block/floppy.c +++ b/drivers/block/floppy.c @@ -3079,7 +3079,7 @@ static void raw_cmd_free(struct floppy_raw_cmd **ptr) } } -#define MAX_LEN (1UL << MAX_ORDER << PAGE_SHIFT) +#define MAX_LEN (1UL << (MAX_ORDER - 1) << PAGE_SHIFT) static int raw_cmd_copyin(int cmd, void __user *param, struct floppy_raw_cmd **rcmd) @@ -3108,7 +3108,7 @@ loop: ptr->resultcode = 0; if (ptr->flags & (FD_RAW_READ | FD_RAW_WRITE)) { - if (ptr->length <= 0 || ptr->length >= MAX_LEN) + if (ptr->length <= 0 || ptr->length > MAX_LEN) return -EINVAL; ptr->kernel_data = (char *)fd_dma_mem_alloc(ptr->length); fallback_on_nodma_alloc(&ptr->kernel_data, ptr->length); |