| Message ID | 20230315113133.11326-4-kirill.shutemov@linux.intel.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | Fix confusion around MAX_ORDER | expand |
On Wed, Mar 15, 2023 at 02:31:26PM +0300, Kirill A. Shutemov wrote: > 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. > > Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> > Cc: Denis Efremov <efremov@linux.com> Acked-by: Mike Rapoport (IBM) <rppt@kernel.org> > --- > drivers/block/floppy.c | 4 ++-- > 1 file 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 @@ static int raw_cmd_copyin(int cmd, void __user *param, > 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); > -- > 2.39.2 >
On 3/15/23 12:31, Kirill A. Shutemov wrote: > 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. > > Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> > Cc: Denis Efremov <efremov@linux.com> > --- > drivers/block/floppy.c | 4 ++-- > 1 file 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 @@ static int raw_cmd_copyin(int cmd, void __user *param, > 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);
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 @@ static int raw_cmd_copyin(int cmd, void __user *param, 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);
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. Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Denis Efremov <efremov@linux.com> --- drivers/block/floppy.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)