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floppy: fix MAX_ORDER usage

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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>
This commit is contained in:
Kirill A. Shutemov 2023-03-15 14:31:26 +03:00 committed by Andrew Morton
parent 254ca6d261
commit 5f29298fba
1 changed files with 2 additions and 2 deletions
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4
drivers/block/floppy.c
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@ -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);