scsi/mvsas/mv_init.c: Use dma_zalloc_coherent

PATCH In review Sabyasachi Gupta 3 participants 9 messages Nov 21, 2018 – Jan 7, 2019 SCSI

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Sabyasachi Gupta

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2018-11-21 13:48 UTC #0 lore raw

PATCH 1/1 scsi/mvsas/mv_init.c: Use dma_zalloc_coherent

Replace dma_alloc_coherent + memset with dma_zalloc_coherent

Signed-off-by Sabyasachi Gupta <[email protected]>

---
 drivers/scsi/mvsas/mv_init.c | 12 ++++--------
 1 file changed, 4 insertions(+), 8 deletions(-)

drivers/scsi/mvsas/mv_init.c +4 -8

index 3ac3437..495bddb 100644
@@ -253,33 +253,29 @@ static int mvs_alloc(struct mvs_info *mvi, struct Scsi_Host *shost)
 	/*
 	 * alloc and init our DMA areas
 	 */
-	mvi->tx = dma_alloc_coherent(mvi->dev,
+	mvi->tx = dma_zalloc_coherent(mvi->dev,
 				     sizeof(*mvi->tx) * MVS_CHIP_SLOT_SZ,
 				     &mvi->tx_dma, GFP_KERNEL);
 	if (!mvi->tx)
 		goto err_out;
-	memset(mvi->tx, 0, sizeof(*mvi->tx) * MVS_CHIP_SLOT_SZ);
-	mvi->rx_fis = dma_alloc_coherent(mvi->dev, MVS_RX_FISL_SZ,
+	mvi->rx_fis = dma_zalloc_coherent(mvi->dev, MVS_RX_FISL_SZ,
 					 &mvi->rx_fis_dma, GFP_KERNEL);
 	if (!mvi->rx_fis)
 		goto err_out;
-	memset(mvi->rx_fis, 0, MVS_RX_FISL_SZ);
 
-	mvi->rx = dma_alloc_coherent(mvi->dev,
+	mvi->rx = dma_zalloc_coherent(mvi->dev,
 				     sizeof(*mvi->rx) * (MVS_RX_RING_SZ + 1),
 				     &mvi->rx_dma, GFP_KERNEL);
 	if (!mvi->rx)
 		goto err_out;
-	memset(mvi->rx, 0, sizeof(*mvi->rx) * (MVS_RX_RING_SZ + 1));
 	mvi->rx[0] = cpu_to_le32(0xfff);
 	mvi->rx_cons = 0xfff;
 
-	mvi->slot = dma_alloc_coherent(mvi->dev,
+	mvi->slot = dma_zalloc_coherent(mvi->dev,
 				       sizeof(*mvi->slot) * slot_nr,
 				       &mvi->slot_dma, GFP_KERNEL);
 	if (!mvi->slot)
 		goto err_out;
-	memset(mvi->slot, 0, sizeof(*mvi->slot) * slot_nr);
 
 	mvi->bulk_buffer = dma_alloc_coherent(mvi->dev,
 				       TRASH_BUCKET_SIZE,

Signature · 1 line

2.7.4

John Garry

2019-01-07 13:50 UTC #8 lore raw

Quoted 22 lines · Souptick Joarder

Quoted 21 lines · John Garry
Quoted 19 lines · Sabyasachi Gupta
Quoted 17 lines · John Garry
Quoted 11 lines · Sabyasachi Gupta
Quoted 9 lines · Sabyasachi Gupta
Quoted 6 lines · Sabyasachi Gupta
Quoted 3 lines · Sabyasachi Gupta
Replace dma_alloc_coherent + memset with dma_zalloc_coherent
If you're going to make this change, then how about change these to the managed version, so that we can avoid the explicit free'ing at driver removal?

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I can't get it
Please see dmam_alloc_coherent(). You can set __GFP_ZERO in the gfp argument to memset(0).
and dma_zalloc_coherent() did the same. So both are same right ? No ?

Firstly I would to say that I am not so keen on changes like this since (I assume) it will not be tested at all.

However, having said that, the reason to use dmam_alloc_coherent() is that you can also drop the dma_free_coherent() in mvs_free(). But changes like that would actually require some code analysis effort...

John

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Quoted 34 lines

I would say that this is a more useful change.
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Signed-off-by Sabyasachi Gupta <[email protected]>
Any comment on this patch?
Any comment on this patch?
Any comment on this patch?
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---
 drivers/scsi/mvsas/mv_init.c | 12 ++++--------
 1 file changed, 4 insertions(+), 8 deletions(-)
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drivers/scsi/mvsas/mv_init.c +0 -0
index 3ac3437..495bddb 100644
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drivers/scsi/mvsas/mv_init.c static int mvs_alloc(struct mvs_info *mvi, struct Scsi_Host *shost) · line 258
Quoted 8 lines
drivers/scsi/mvsas/mv_init.c +1 -1
@@ -253,33 +253,29 @@ static int mvs_alloc(struct mvs_info *mvi, struct Scsi_Host *shost)
        /*
         * alloc and init our DMA areas
         */
-       mvi->tx = dma_alloc_coherent(mvi->dev,
+       mvi->tx = dma_zalloc_coherent(mvi->dev,
                                     sizeof(*mvi->tx) * MVS_CHIP_SLOT_SZ,
                                     &mvi->tx_dma, GFP_KERNEL);
I'm guessing that this does not pass checkpatch with --strict option.

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Thanks,
John
I have not not checked with --strict option

It may warn that you're not maintaining alignment.

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drivers/scsi/mvsas/mv_init.c +3 -7

        if (!mvi->tx)
                goto err_out;
-       memset(mvi->tx, 0, sizeof(*mvi->tx) * MVS_CHIP_SLOT_SZ);
-       mvi->rx_fis = dma_alloc_coherent(mvi->dev, MVS_RX_FISL_SZ,
+       mvi->rx_fis = dma_zalloc_coherent(mvi->dev, MVS_RX_FISL_SZ,
                                         &mvi->rx_fis_dma, GFP_KERNEL);
        if (!mvi->rx_fis)
                goto err_out;
-       memset(mvi->rx_fis, 0, MVS_RX_FISL_SZ);
 
-       mvi->rx = dma_alloc_coherent(mvi->dev,
+       mvi->rx = dma_zalloc_coherent(mvi->dev,
                                     sizeof(*mvi->rx) * (MVS_RX_RING_SZ + 1),
                                     &mvi->rx_dma, GFP_KERNEL);
        if (!mvi->rx)
                goto err_out;
-       memset(mvi->rx, 0, sizeof(*mvi->rx) * (MVS_RX_RING_SZ + 1));
        mvi->rx[0] = cpu_to_le32(0xfff);
        mvi->rx_cons = 0xfff;
 
-       mvi->slot = dma_alloc_coherent(mvi->dev,
+       mvi->slot = dma_zalloc_coherent(mvi->dev,
                                       sizeof(*mvi->slot) * slot_nr,
                                       &mvi->slot_dma, GFP_KERNEL);
        if (!mvi->slot)
                goto err_out;
-       memset(mvi->slot, 0, sizeof(*mvi->slot) * slot_nr);

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drivers/scsi/mvsas/mv_init.c +0 -1

        mvi->bulk_buffer = dma_alloc_coherent(mvi->dev,
                                       TRASH_BUCKET_SIZE,
--

2.7.4