* [PATCH RESEND v3] mmc: core: Remove bounce buffer in mmc_send_cxd_data()
@ 2012-07-31 2:00 Kyungsik Lee
2012-07-31 7:19 ` S, Venkatraman
0 siblings, 1 reply; 3+ messages in thread
From: Kyungsik Lee @ 2012-07-31 2:00 UTC (permalink / raw)
To: Chris Ball
Cc: Venkatraman S, Jaehoon Chung, raphael.andy.lee, linux-mmc,
linux-kernel, Kyungsik Lee
It is expected that Extended CSD register(the size of this register
is larger than CID/CSD) will be referenced more frequently as more
fields have been added to Extended CSD and it seems that it is not
a good option to double the memory used.
This patch is intended to avoid the use of bounce buffer for reading
Extended CSD register in mmc_send_cxd_data().
Signed-off-by: Kyungsik Lee <kyungsik.lee@lge.com>
---
Changes in v2:
- Handling on-stack buffer if it's used in caller.
Changes in v3:
- Remove unnecesary code.
---
drivers/mmc/core/mmc_ops.c | 54 ++++++++++++++++++++++++++++++++-----------
1 files changed, 40 insertions(+), 14 deletions(-)
diff --git a/drivers/mmc/core/mmc_ops.c b/drivers/mmc/core/mmc_ops.c
index 0ed2cc5..036e6d5 100644
--- a/drivers/mmc/core/mmc_ops.c
+++ b/drivers/mmc/core/mmc_ops.c
@@ -239,13 +239,19 @@ mmc_send_cxd_data(struct mmc_card *card, struct mmc_host *host,
struct mmc_data data = {0};
struct scatterlist sg;
void *data_buf;
+ int is_on_stack;
- /* dma onto stack is unsafe/nonportable, but callers to this
- * routine normally provide temporary on-stack buffers ...
- */
- data_buf = kmalloc(len, GFP_KERNEL);
- if (data_buf == NULL)
- return -ENOMEM;
+ is_on_stack = object_is_on_stack(buf);
+ if (is_on_stack) {
+
+ /* dma onto stack is unsafe/nonportable, but callers to this
+ * routine normally provide temporary on-stack buffers ...
+ */
+ data_buf = kmalloc(len, GFP_KERNEL);
+ if (data_buf == NULL)
+ return -ENOMEM;
+ } else
+ data_buf = buf;
mrq.cmd = &cmd;
mrq.data = &data;
@@ -280,8 +286,10 @@ mmc_send_cxd_data(struct mmc_card *card, struct mmc_host *host,
mmc_wait_for_req(host, &mrq);
- memcpy(buf, data_buf, len);
- kfree(data_buf);
+ if (is_on_stack) {
+ memcpy(buf, data_buf, len);
+ kfree(data_buf);
+ }
if (cmd.error)
return cmd.error;
@@ -294,24 +302,34 @@ mmc_send_cxd_data(struct mmc_card *card, struct mmc_host *host,
int mmc_send_csd(struct mmc_card *card, u32 *csd)
{
int ret, i;
+ u32 *csd_tmp;
if (!mmc_host_is_spi(card->host))
return mmc_send_cxd_native(card->host, card->rca << 16,
csd, MMC_SEND_CSD);
- ret = mmc_send_cxd_data(card, card->host, MMC_SEND_CSD, csd, 16);
+ csd_tmp = kmalloc(16, GFP_KERNEL);
+ if (!csd_tmp)
+ return -ENOMEM;
+
+ ret = mmc_send_cxd_data(card, card->host, MMC_SEND_CSD, csd_tmp, 16);
if (ret)
- return ret;
+ goto err;
+
+ memcpy(csd, csd_tmp, 16);
for (i = 0;i < 4;i++)
csd[i] = be32_to_cpu(csd[i]);
- return 0;
+err:
+ kfree(csd_tmp);
+ return ret;
}
int mmc_send_cid(struct mmc_host *host, u32 *cid)
{
int ret, i;
+ u32 *cid_tmp;
if (!mmc_host_is_spi(host)) {
if (!host->card)
@@ -320,14 +338,22 @@ int mmc_send_cid(struct mmc_host *host, u32 *cid)
cid, MMC_SEND_CID);
}
- ret = mmc_send_cxd_data(NULL, host, MMC_SEND_CID, cid, 16);
+ cid_tmp = kmalloc(16, GFP_KERNEL);
+ if (!cid_tmp)
+ return -ENOMEM;
+
+ ret = mmc_send_cxd_data(NULL, host, MMC_SEND_CID, cid_tmp, 16);
if (ret)
- return ret;
+ goto err;
+
+ memcpy(cid, cid_tmp, 16);
for (i = 0;i < 4;i++)
cid[i] = be32_to_cpu(cid[i]);
- return 0;
+err:
+ kfree(cid_tmp);
+ return ret;
}
int mmc_send_ext_csd(struct mmc_card *card, u8 *ext_csd)
--
1.7.0.4
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH RESEND v3] mmc: core: Remove bounce buffer in mmc_send_cxd_data()
2012-07-31 2:00 [PATCH RESEND v3] mmc: core: Remove bounce buffer in mmc_send_cxd_data() Kyungsik Lee
@ 2012-07-31 7:19 ` S, Venkatraman
2012-07-31 8:37 ` kyungsik.lee
0 siblings, 1 reply; 3+ messages in thread
From: S, Venkatraman @ 2012-07-31 7:19 UTC (permalink / raw)
To: Kyungsik Lee
Cc: Chris Ball, Jaehoon Chung, raphael.andy.lee, linux-mmc, linux-kernel
On Tue, Jul 31, 2012 at 7:30 AM, Kyungsik Lee <kyungsik.lee@lge.com> wrote:
> It is expected that Extended CSD register(the size of this register
> is larger than CID/CSD) will be referenced more frequently as more
> fields have been added to Extended CSD and it seems that it is not
> a good option to double the memory used.
>
> This patch is intended to avoid the use of bounce buffer for reading
> Extended CSD register in mmc_send_cxd_data().
>
> Signed-off-by: Kyungsik Lee <kyungsik.lee@lge.com>
> ---
> Changes in v2:
> - Handling on-stack buffer if it's used in caller.
>
> Changes in v3:
> - Remove unnecesary code.
> ---
> drivers/mmc/core/mmc_ops.c | 54 ++++++++++++++++++++++++++++++++-----------
> 1 files changed, 40 insertions(+), 14 deletions(-)
>
> diff --git a/drivers/mmc/core/mmc_ops.c b/drivers/mmc/core/mmc_ops.c
> index 0ed2cc5..036e6d5 100644
> --- a/drivers/mmc/core/mmc_ops.c
> +++ b/drivers/mmc/core/mmc_ops.c
> @@ -239,13 +239,19 @@ mmc_send_cxd_data(struct mmc_card *card, struct mmc_host *host,
> struct mmc_data data = {0};
> struct scatterlist sg;
> void *data_buf;
> + int is_on_stack;
>
> - /* dma onto stack is unsafe/nonportable, but callers to this
> - * routine normally provide temporary on-stack buffers ...
> - */
> - data_buf = kmalloc(len, GFP_KERNEL);
> - if (data_buf == NULL)
> - return -ENOMEM;
> + is_on_stack = object_is_on_stack(buf);
> + if (is_on_stack) {
> +
> + /* dma onto stack is unsafe/nonportable, but callers to this
> + * routine normally provide temporary on-stack buffers ...
> + */
> + data_buf = kmalloc(len, GFP_KERNEL);
> + if (data_buf == NULL)
> + return -ENOMEM;
> + } else
> + data_buf = buf;
>
> mrq.cmd = &cmd;
> mrq.data = &data;
> @@ -280,8 +286,10 @@ mmc_send_cxd_data(struct mmc_card *card, struct mmc_host *host,
>
> mmc_wait_for_req(host, &mrq);
>
> - memcpy(buf, data_buf, len);
> - kfree(data_buf);
> + if (is_on_stack) {
> + memcpy(buf, data_buf, len);
> + kfree(data_buf);
> + }
>
> if (cmd.error)
> return cmd.error;
> @@ -294,24 +302,34 @@ mmc_send_cxd_data(struct mmc_card *card, struct mmc_host *host,
> int mmc_send_csd(struct mmc_card *card, u32 *csd)
> {
> int ret, i;
> + u32 *csd_tmp;
>
> if (!mmc_host_is_spi(card->host))
> return mmc_send_cxd_native(card->host, card->rca << 16,
> csd, MMC_SEND_CSD);
>
> - ret = mmc_send_cxd_data(card, card->host, MMC_SEND_CSD, csd, 16);
> + csd_tmp = kmalloc(16, GFP_KERNEL);
> + if (!csd_tmp)
> + return -ENOMEM;
> +
> + ret = mmc_send_cxd_data(card, card->host, MMC_SEND_CSD, csd_tmp, 16);
> if (ret)
> - return ret;
> + goto err;
> +
> + memcpy(csd, csd_tmp, 16);
Can this memcpy be folded into the for loop below
as for (....) { csd[i] = be32_to_cpu(csd_tmp[i]); ?
>
> for (i = 0;i < 4;i++)
> csd[i] = be32_to_cpu(csd[i]);
>
> - return 0;
> +err:
> + kfree(csd_tmp);
> + return ret;
> }
>
> int mmc_send_cid(struct mmc_host *host, u32 *cid)
> {
> int ret, i;
> + u32 *cid_tmp;
>
> if (!mmc_host_is_spi(host)) {
> if (!host->card)
> @@ -320,14 +338,22 @@ int mmc_send_cid(struct mmc_host *host, u32 *cid)
> cid, MMC_SEND_CID);
> }
>
> - ret = mmc_send_cxd_data(NULL, host, MMC_SEND_CID, cid, 16);
> + cid_tmp = kmalloc(16, GFP_KERNEL);
> + if (!cid_tmp)
> + return -ENOMEM;
> +
> + ret = mmc_send_cxd_data(NULL, host, MMC_SEND_CID, cid_tmp, 16);
> if (ret)
> - return ret;
> + goto err;
> +
> + memcpy(cid, cid_tmp, 16);
>
<Same comment as above>
> for (i = 0;i < 4;i++)
> cid[i] = be32_to_cpu(cid[i]);
>
> - return 0;
> +err:
> + kfree(cid_tmp);
> + return ret;
> }
>
> int mmc_send_ext_csd(struct mmc_card *card, u8 *ext_csd)
> --
> 1.7.0.4
>
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH RESEND v3] mmc: core: Remove bounce buffer in mmc_send_cxd_data()
2012-07-31 7:19 ` S, Venkatraman
@ 2012-07-31 8:37 ` kyungsik.lee
0 siblings, 0 replies; 3+ messages in thread
From: kyungsik.lee @ 2012-07-31 8:37 UTC (permalink / raw)
To: S, Venkatraman
Cc: Chris Ball, Jaehoon Chung, raphael.andy.lee, linux-mmc, linux-kernel
On 2012-07-31 오후 4:19, S, Venkatraman wrote:
> On Tue, Jul 31, 2012 at 7:30 AM, Kyungsik Lee <kyungsik.lee@lge.com> wrote:
>> It is expected that Extended CSD register(the size of this register
>> is larger than CID/CSD) will be referenced more frequently as more
>> fields have been added to Extended CSD and it seems that it is not
>> a good option to double the memory used.
>>
>> This patch is intended to avoid the use of bounce buffer for reading
>> Extended CSD register in mmc_send_cxd_data().
>>
>> Signed-off-by: Kyungsik Lee <kyungsik.lee@lge.com>
>> ---
>> Changes in v2:
>> - Handling on-stack buffer if it's used in caller.
>>
>> Changes in v3:
>> - Remove unnecesary code.
>> ---
>> drivers/mmc/core/mmc_ops.c | 54 ++++++++++++++++++++++++++++++++-----------
>> 1 files changed, 40 insertions(+), 14 deletions(-)
>>
>> diff --git a/drivers/mmc/core/mmc_ops.c b/drivers/mmc/core/mmc_ops.c
>> index 0ed2cc5..036e6d5 100644
>> --- a/drivers/mmc/core/mmc_ops.c
>> +++ b/drivers/mmc/core/mmc_ops.c
>> @@ -239,13 +239,19 @@ mmc_send_cxd_data(struct mmc_card *card, struct mmc_host *host,
>> struct mmc_data data = {0};
>> struct scatterlist sg;
>> void *data_buf;
>> + int is_on_stack;
>>
>> - /* dma onto stack is unsafe/nonportable, but callers to this
>> - * routine normally provide temporary on-stack buffers ...
>> - */
>> - data_buf = kmalloc(len, GFP_KERNEL);
>> - if (data_buf == NULL)
>> - return -ENOMEM;
>> + is_on_stack = object_is_on_stack(buf);
>> + if (is_on_stack) {
>> +
>> + /* dma onto stack is unsafe/nonportable, but callers to this
>> + * routine normally provide temporary on-stack buffers ...
>> + */
>> + data_buf = kmalloc(len, GFP_KERNEL);
>> + if (data_buf == NULL)
>> + return -ENOMEM;
>> + } else
>> + data_buf = buf;
>>
>> mrq.cmd = &cmd;
>> mrq.data = &data;
>> @@ -280,8 +286,10 @@ mmc_send_cxd_data(struct mmc_card *card, struct mmc_host *host,
>>
>> mmc_wait_for_req(host, &mrq);
>>
>> - memcpy(buf, data_buf, len);
>> - kfree(data_buf);
>> + if (is_on_stack) {
>> + memcpy(buf, data_buf, len);
>> + kfree(data_buf);
>> + }
>>
>> if (cmd.error)
>> return cmd.error;
>> @@ -294,24 +302,34 @@ mmc_send_cxd_data(struct mmc_card *card, struct mmc_host *host,
>> int mmc_send_csd(struct mmc_card *card, u32 *csd)
>> {
>> int ret, i;
>> + u32 *csd_tmp;
>>
>> if (!mmc_host_is_spi(card->host))
>> return mmc_send_cxd_native(card->host, card->rca << 16,
>> csd, MMC_SEND_CSD);
>>
>> - ret = mmc_send_cxd_data(card, card->host, MMC_SEND_CSD, csd, 16);
>> + csd_tmp = kmalloc(16, GFP_KERNEL);
>> + if (!csd_tmp)
>> + return -ENOMEM;
>> +
>> + ret = mmc_send_cxd_data(card, card->host, MMC_SEND_CSD, csd_tmp, 16);
>> if (ret)
>> - return ret;
>> + goto err;
>> +
>> + memcpy(csd, csd_tmp, 16);
> Can this memcpy be folded into the for loop below
> as for (....) { csd[i] = be32_to_cpu(csd_tmp[i]); ?
Yes, you're right. I will fix it as you suggested.
Thanks,
Kyungsik Lee
>> for (i = 0;i < 4;i++)
>> csd[i] = be32_to_cpu(csd[i]);
>>
>> - return 0;
>> +err:
>> + kfree(csd_tmp);
>> + return ret;
>> }
>>
>> int mmc_send_cid(struct mmc_host *host, u32 *cid)
>> {
>> int ret, i;
>> + u32 *cid_tmp;
>>
>> if (!mmc_host_is_spi(host)) {
>> if (!host->card)
>> @@ -320,14 +338,22 @@ int mmc_send_cid(struct mmc_host *host, u32 *cid)
>> cid, MMC_SEND_CID);
>> }
>>
>> - ret = mmc_send_cxd_data(NULL, host, MMC_SEND_CID, cid, 16);
>> + cid_tmp = kmalloc(16, GFP_KERNEL);
>> + if (!cid_tmp)
>> + return -ENOMEM;
>> +
>> + ret = mmc_send_cxd_data(NULL, host, MMC_SEND_CID, cid_tmp, 16);
>> if (ret)
>> - return ret;
>> + goto err;
>> +
>> + memcpy(cid, cid_tmp, 16);
>>
> <Same comment as above>
>
>> for (i = 0;i < 4;i++)
>> cid[i] = be32_to_cpu(cid[i]);
>>
>> - return 0;
>> +err:
>> + kfree(cid_tmp);
>> + return ret;
>> }
>>
>> int mmc_send_ext_csd(struct mmc_card *card, u8 *ext_csd)
>> --
>> 1.7.0.4
>>
^ permalink raw reply [flat|nested] 3+ messages in thread
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2012-07-31 2:00 [PATCH RESEND v3] mmc: core: Remove bounce buffer in mmc_send_cxd_data() Kyungsik Lee
2012-07-31 7:19 ` S, Venkatraman
2012-07-31 8:37 ` kyungsik.lee
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