| Message ID | 20190115194153.GA9565@embeddedor (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [net-next] libceph, ceph: use struct_size() in kmalloc() | expand |
On Tue, Jan 15, 2019 at 8:41 PM Gustavo A. R. Silva <gustavo@embeddedor.com> wrote: > > One of the more common cases of allocation size calculations is finding > the size of a structure that has a zero-sized array at the end, along > with memory for some number of elements for that array. For example: > > struct foo { > int stuff; > struct boo entry[]; > }; > > instance = kmalloc(sizeof(struct foo) + count * sizeof(struct boo), GFP_KERNEL); > > Instead of leaving these open-coded and prone to type mistakes, we can > now use the new struct_size() helper: > > instance = kmalloc(struct_size(instance, entry, count), GFP_KERNEL); > > This code was detected with the help of Coccinelle. > > Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com> > --- > net/ceph/osdmap.c | 5 ++--- > 1 file changed, 2 insertions(+), 3 deletions(-) > > diff --git a/net/ceph/osdmap.c b/net/ceph/osdmap.c > index 98c0ff3d6441..48a31dc9161c 100644 > --- a/net/ceph/osdmap.c > +++ b/net/ceph/osdmap.c > @@ -495,9 +495,8 @@ static struct crush_map *crush_decode(void *pbyval, void *end) > / sizeof(struct crush_rule_step)) > goto bad; > #endif > - r = c->rules[i] = kmalloc(sizeof(*r) + > - yes*sizeof(struct crush_rule_step), > - GFP_NOFS); > + r = kmalloc(struct_size(r, steps, yes), GFP_NOFS); > + c->rules[i] = r; > if (r == NULL) > goto badmem; > dout(" rule %d is at %p\n", i, r); Applied. Thanks, Ilya
On 1/17/19 8:17 AM, Ilya Dryomov wrote: > On Tue, Jan 15, 2019 at 8:41 PM Gustavo A. R. Silva > <gustavo@embeddedor.com> wrote: >> >> One of the more common cases of allocation size calculations is finding >> the size of a structure that has a zero-sized array at the end, along >> with memory for some number of elements for that array. For example: >> >> struct foo { >> int stuff; >> struct boo entry[]; >> }; >> >> instance = kmalloc(sizeof(struct foo) + count * sizeof(struct boo), GFP_KERNEL); >> >> Instead of leaving these open-coded and prone to type mistakes, we can >> now use the new struct_size() helper: >> >> instance = kmalloc(struct_size(instance, entry, count), GFP_KERNEL); >> >> This code was detected with the help of Coccinelle. >> >> Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com> >> --- >> net/ceph/osdmap.c | 5 ++--- >> 1 file changed, 2 insertions(+), 3 deletions(-) >> >> diff --git a/net/ceph/osdmap.c b/net/ceph/osdmap.c >> index 98c0ff3d6441..48a31dc9161c 100644 >> --- a/net/ceph/osdmap.c >> +++ b/net/ceph/osdmap.c >> @@ -495,9 +495,8 @@ static struct crush_map *crush_decode(void *pbyval, void *end) >> / sizeof(struct crush_rule_step)) >> goto bad; >> #endif >> - r = c->rules[i] = kmalloc(sizeof(*r) + >> - yes*sizeof(struct crush_rule_step), >> - GFP_NOFS); >> + r = kmalloc(struct_size(r, steps, yes), GFP_NOFS); >> + c->rules[i] = r; >> if (r == NULL) >> goto badmem; >> dout(" rule %d is at %p\n", i, r); > > Applied. > Thanks, Ilya. -- Gustavo
diff --git a/net/ceph/osdmap.c b/net/ceph/osdmap.c index 98c0ff3d6441..48a31dc9161c 100644 --- a/net/ceph/osdmap.c +++ b/net/ceph/osdmap.c @@ -495,9 +495,8 @@ static struct crush_map *crush_decode(void *pbyval, void *end) / sizeof(struct crush_rule_step)) goto bad; #endif - r = c->rules[i] = kmalloc(sizeof(*r) + - yes*sizeof(struct crush_rule_step), - GFP_NOFS); + r = kmalloc(struct_size(r, steps, yes), GFP_NOFS); + c->rules[i] = r; if (r == NULL) goto badmem; dout(" rule %d is at %p\n", i, r);
One of the more common cases of allocation size calculations is finding the size of a structure that has a zero-sized array at the end, along with memory for some number of elements for that array. For example: struct foo { int stuff; struct boo entry[]; }; instance = kmalloc(sizeof(struct foo) + count * sizeof(struct boo), GFP_KERNEL); Instead of leaving these open-coded and prone to type mistakes, we can now use the new struct_size() helper: instance = kmalloc(struct_size(instance, entry, count), GFP_KERNEL); This code was detected with the help of Coccinelle. Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com> --- net/ceph/osdmap.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-)