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R. Silva" , linux-kernel@vger.kernel.org (open list), linux-hardening@vger.kernel.org (open list:KERNEL HARDENING (not covered by other areas):Keyword:\b__counted_by(_le|_be)?\b) Subject: [PATCHv2] dmaengine: idma64: use kzalloc_flex Date: Fri, 20 Mar 2026 20:49:31 -0700 Message-ID: <20260321034931.9950-1-rosenp@gmail.com> X-Mailer: git-send-email 2.53.0 Precedence: bulk X-Mailing-List: linux-hardening@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Simplifies allocations by using a flexible array member in this struct. Remove idma64_alloc_desc. It now offers no readability advantages in this single usage. Add __counted_by to get extra runtime analysis. Apply the exact same treatment to struct idma64_dma and devm_kzalloc. Signed-off-by: Rosen Penev --- v2: allocate with GFP_NOWAIT. Was mistakenly removed. drivers/dma/idma64.c | 30 ++++-------------------------- drivers/dma/idma64.h | 4 ++-- 2 files changed, 6 insertions(+), 28 deletions(-) diff --git a/drivers/dma/idma64.c b/drivers/dma/idma64.c index 5fcd1befc92d..d914f50ec309 100644 --- a/drivers/dma/idma64.c +++ b/drivers/dma/idma64.c @@ -192,23 +192,6 @@ static irqreturn_t idma64_irq(int irq, void *dev) /* ---------------------------------------------------------------------- */ -static struct idma64_desc *idma64_alloc_desc(unsigned int ndesc) -{ - struct idma64_desc *desc; - - desc = kzalloc_obj(*desc, GFP_NOWAIT); - if (!desc) - return NULL; - - desc->hw = kzalloc_objs(*desc->hw, ndesc, GFP_NOWAIT); - if (!desc->hw) { - kfree(desc); - return NULL; - } - - return desc; -} - static void idma64_desc_free(struct idma64_chan *idma64c, struct idma64_desc *desc) { @@ -223,7 +206,6 @@ static void idma64_desc_free(struct idma64_chan *idma64c, } while (i); } - kfree(desc->hw); kfree(desc); } @@ -307,10 +289,12 @@ static struct dma_async_tx_descriptor *idma64_prep_slave_sg( struct scatterlist *sg; unsigned int i; - desc = idma64_alloc_desc(sg_len); + desc = kzalloc_flex(*desc, hw, sg_len, GFP_NOWAIT); if (!desc) return NULL; + desc->ndesc = sg_len; + for_each_sg(sgl, sg, sg_len, i) { struct idma64_hw_desc *hw = &desc->hw[i]; @@ -326,7 +310,6 @@ static struct dma_async_tx_descriptor *idma64_prep_slave_sg( hw->len = sg_dma_len(sg); } - desc->ndesc = sg_len; desc->direction = direction; desc->status = DMA_IN_PROGRESS; @@ -541,18 +524,13 @@ static int idma64_probe(struct idma64_chip *chip) unsigned short i; int ret; - idma64 = devm_kzalloc(chip->dev, sizeof(*idma64), GFP_KERNEL); + idma64 = devm_kzalloc(chip->dev, struct_size(idma64, chan, nr_chan), GFP_KERNEL); if (!idma64) return -ENOMEM; idma64->regs = chip->regs; chip->idma64 = idma64; - idma64->chan = devm_kcalloc(chip->dev, nr_chan, sizeof(*idma64->chan), - GFP_KERNEL); - if (!idma64->chan) - return -ENOMEM; - idma64->all_chan_mask = (1 << nr_chan) - 1; /* Turn off iDMA controller */ diff --git a/drivers/dma/idma64.h b/drivers/dma/idma64.h index d013b54356aa..1a67dbb24db5 100644 --- a/drivers/dma/idma64.h +++ b/drivers/dma/idma64.h @@ -113,10 +113,10 @@ struct idma64_hw_desc { struct idma64_desc { struct virt_dma_desc vdesc; enum dma_transfer_direction direction; - struct idma64_hw_desc *hw; unsigned int ndesc; size_t length; enum dma_status status; + struct idma64_hw_desc hw[] __counted_by(ndesc); }; static inline struct idma64_desc *to_idma64_desc(struct virt_dma_desc *vdesc) @@ -187,7 +187,7 @@ struct idma64 { /* channels */ unsigned short all_chan_mask; - struct idma64_chan *chan; + struct idma64_chan chan[]; }; static inline struct idma64 *to_idma64(struct dma_device *ddev) -- 2.53.0