| Message ID | 20220922031013.2150682-4-keescook@chromium.org (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | slab: Introduce kmalloc_size_roundup() | expand |
On 9/21/22 10:10 PM, Kees Cook wrote: > Instead of discovering the kmalloc bucket size _after_ allocation, round > up proactively so the allocation is explicitly made for the full size, > allowing the compiler to correctly reason about the resulting size of > the buffer through the existing __alloc_size() hint. > > Cc: Alex Elder <elder@kernel.org> > Cc: "David S. Miller" <davem@davemloft.net> > Cc: Eric Dumazet <edumazet@google.com> > Cc: Jakub Kicinski <kuba@kernel.org> > Cc: Paolo Abeni <pabeni@redhat.com> > Cc: netdev@vger.kernel.org > Signed-off-by: Kees Cook <keescook@chromium.org> > --- > drivers/net/ipa/gsi_trans.c | 7 +++++-- > 1 file changed, 5 insertions(+), 2 deletions(-) > > diff --git a/drivers/net/ipa/gsi_trans.c b/drivers/net/ipa/gsi_trans.c > index 18e7e8c405be..cec968854dcf 100644 > --- a/drivers/net/ipa/gsi_trans.c > +++ b/drivers/net/ipa/gsi_trans.c > @@ -89,6 +89,7 @@ int gsi_trans_pool_init(struct gsi_trans_pool *pool, size_t size, u32 count, > u32 max_alloc) > { > void *virt; > + size_t allocate; I don't care about this but the reverse Christmas tree convention would put the "allocate" variable definition above "virt". Whether you fix that or not, this patch looks good to me. Reviewed-by: Alex Elder <elder@linaro.org> > if (!size) > return -EINVAL; > @@ -104,13 +105,15 @@ int gsi_trans_pool_init(struct gsi_trans_pool *pool, size_t size, u32 count, > * If there aren't enough entries starting at the free index, > * we just allocate free entries from the beginning of the pool. > */ > - virt = kcalloc(count + max_alloc - 1, size, GFP_KERNEL); > + allocate = size_mul(count + max_alloc - 1, size); > + allocate = kmalloc_size_roundup(allocate); > + virt = kzalloc(allocate, GFP_KERNEL); > if (!virt) > return -ENOMEM; > > pool->base = virt; > /* If the allocator gave us any extra memory, use it */ > - pool->count = ksize(pool->base) / size; > + pool->count = allocate / size; > pool->free = 0; > pool->max_alloc = max_alloc; > pool->size = size;
On Thu, Sep 22, 2022 at 08:45:19AM -0500, Alex Elder wrote: > On 9/21/22 10:10 PM, Kees Cook wrote: > > Instead of discovering the kmalloc bucket size _after_ allocation, round > > up proactively so the allocation is explicitly made for the full size, > > allowing the compiler to correctly reason about the resulting size of > > the buffer through the existing __alloc_size() hint. > > > > Cc: Alex Elder <elder@kernel.org> > > Cc: "David S. Miller" <davem@davemloft.net> > > Cc: Eric Dumazet <edumazet@google.com> > > Cc: Jakub Kicinski <kuba@kernel.org> > > Cc: Paolo Abeni <pabeni@redhat.com> > > Cc: netdev@vger.kernel.org > > Signed-off-by: Kees Cook <keescook@chromium.org> > > --- > > drivers/net/ipa/gsi_trans.c | 7 +++++-- > > 1 file changed, 5 insertions(+), 2 deletions(-) > > > > diff --git a/drivers/net/ipa/gsi_trans.c b/drivers/net/ipa/gsi_trans.c > > index 18e7e8c405be..cec968854dcf 100644 > > --- a/drivers/net/ipa/gsi_trans.c > > +++ b/drivers/net/ipa/gsi_trans.c > > @@ -89,6 +89,7 @@ int gsi_trans_pool_init(struct gsi_trans_pool *pool, size_t size, u32 count, > > u32 max_alloc) > > { > > void *virt; > > + size_t allocate; > > I don't care about this but the reverse Christmas tree > convention would put the "allocate" variable definition > above "virt". Oops, yes; thank you! -Kees
diff --git a/drivers/net/ipa/gsi_trans.c b/drivers/net/ipa/gsi_trans.c index 18e7e8c405be..cec968854dcf 100644 --- a/drivers/net/ipa/gsi_trans.c +++ b/drivers/net/ipa/gsi_trans.c @@ -89,6 +89,7 @@ int gsi_trans_pool_init(struct gsi_trans_pool *pool, size_t size, u32 count, u32 max_alloc) { void *virt; + size_t allocate; if (!size) return -EINVAL; @@ -104,13 +105,15 @@ int gsi_trans_pool_init(struct gsi_trans_pool *pool, size_t size, u32 count, * If there aren't enough entries starting at the free index, * we just allocate free entries from the beginning of the pool. */ - virt = kcalloc(count + max_alloc - 1, size, GFP_KERNEL); + allocate = size_mul(count + max_alloc - 1, size); + allocate = kmalloc_size_roundup(allocate); + virt = kzalloc(allocate, GFP_KERNEL); if (!virt) return -ENOMEM; pool->base = virt; /* If the allocator gave us any extra memory, use it */ - pool->count = ksize(pool->base) / size; + pool->count = allocate / size; pool->free = 0; pool->max_alloc = max_alloc; pool->size = size;
Instead of discovering the kmalloc bucket size _after_ allocation, round up proactively so the allocation is explicitly made for the full size, allowing the compiler to correctly reason about the resulting size of the buffer through the existing __alloc_size() hint. Cc: Alex Elder <elder@kernel.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Eric Dumazet <edumazet@google.com> Cc: Jakub Kicinski <kuba@kernel.org> Cc: Paolo Abeni <pabeni@redhat.com> Cc: netdev@vger.kernel.org Signed-off-by: Kees Cook <keescook@chromium.org> --- drivers/net/ipa/gsi_trans.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-)