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SubjectRe: [PATCH v4 1/4] block: add a flag to identify PM request
Date
On Thursday, July 05, 2012, Lin Ming wrote:
> Add a flag REQ_PM to identify the request is PM related.
> As an example, modify scsi code to use this flag.
>
> Signed-off-by: Lin Ming <ming.m.lin@intel.com>
> ---
> drivers/scsi/scsi_lib.c | 25 ++++++++++++++++++++++---
> drivers/scsi/sd.c | 9 +++++----
> include/linux/blk_types.h | 2 ++
> include/scsi/scsi_device.h | 4 ++++
> 4 files changed, 33 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
> index 6dfb978..45538e5 100644
> --- a/drivers/scsi/scsi_lib.c
> +++ b/drivers/scsi/scsi_lib.c
> @@ -256,10 +256,10 @@ int scsi_execute(struct scsi_device *sdev, const unsigned char *cmd,
> EXPORT_SYMBOL(scsi_execute);
>
>
> -int scsi_execute_req(struct scsi_device *sdev, const unsigned char *cmd,
> +static int __scsi_execute_req(struct scsi_device *sdev, const unsigned char *cmd,
> int data_direction, void *buffer, unsigned bufflen,
> struct scsi_sense_hdr *sshdr, int timeout, int retries,
> - int *resid)
> + int *resid, int flags)
> {
> char *sense = NULL;
> int result;
> @@ -270,15 +270,34 @@ int scsi_execute_req(struct scsi_device *sdev, const unsigned char *cmd,
> return DRIVER_ERROR << 24;
> }
> result = scsi_execute(sdev, cmd, data_direction, buffer, bufflen,
> - sense, timeout, retries, 0, resid);
> + sense, timeout, retries, flags, resid);
> if (sshdr)
> scsi_normalize_sense(sense, SCSI_SENSE_BUFFERSIZE, sshdr);
>
> kfree(sense);
> return result;
> }
> +
> +int scsi_execute_req(struct scsi_device *sdev, const unsigned char *cmd,
> + int data_direction, void *buffer, unsigned bufflen,
> + struct scsi_sense_hdr *sshdr, int timeout, int retries,
> + int *resid)
> +{
> + return __scsi_execute_req(sdev, cmd, data_direction, buffer, bufflen,
> + sshdr, timeout, retries, resid, 0);
> +}
> EXPORT_SYMBOL(scsi_execute_req);
>
> +int scsi_execute_req_flag(struct scsi_device *sdev, const unsigned char *cmd,
> + int data_direction, void *buffer, unsigned bufflen,
> + struct scsi_sense_hdr *sshdr, int timeout, int retries,
> + int *resid, int flags)
> +{
> + return __scsi_execute_req(sdev, cmd, data_direction, buffer, bufflen,
> + sshdr, timeout, retries, resid, flags);
> +}
> +EXPORT_SYMBOL(scsi_execute_req_flag);

Hmm. You're only adding one item to the call chain this way and with many
arguments. I think it would be better to export __scsi_execute_req()
directly and define the wrappers as static inlines in a header.

In which case you won't need the second wrapper even. So perhaps it would be
a good idea to call the function scsi_execute_req_flags() and add a static
inline wrapper called scsi_execute_req() around it that will pass 0 as flags?

Rafael


> +
> /*
> * Function: scsi_init_cmd_errh()
> *
> diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
> index 6f72b80..bf8413a 100644
> --- a/drivers/scsi/sd.c
> +++ b/drivers/scsi/sd.c
> @@ -1270,8 +1270,9 @@ static int sd_sync_cache(struct scsi_disk *sdkp)
> * Leave the rest of the command zero to indicate
> * flush everything.
> */
> - res = scsi_execute_req(sdp, cmd, DMA_NONE, NULL, 0, &sshdr,
> - SD_FLUSH_TIMEOUT, SD_MAX_RETRIES, NULL);
> + res = scsi_execute_req_flag(sdp, cmd, DMA_NONE, NULL, 0, &sshdr,
> + SD_FLUSH_TIMEOUT, SD_MAX_RETRIES, NULL,
> + REQ_PM);
> if (res == 0)
> break;
> }
> @@ -2815,8 +2816,8 @@ static int sd_start_stop_device(struct scsi_disk *sdkp, int start)
> if (!scsi_device_online(sdp))
> return -ENODEV;
>
> - res = scsi_execute_req(sdp, cmd, DMA_NONE, NULL, 0, &sshdr,
> - SD_TIMEOUT, SD_MAX_RETRIES, NULL);
> + res = scsi_execute_req_flag(sdp, cmd, DMA_NONE, NULL, 0, &sshdr,
> + SD_TIMEOUT, SD_MAX_RETRIES, NULL, REQ_PM);
> if (res) {
> sd_printk(KERN_WARNING, sdkp, "START_STOP FAILED\n");
> sd_print_result(sdkp, res);
> diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
> index 0edb65d..ed53dca 100644
> --- a/include/linux/blk_types.h
> +++ b/include/linux/blk_types.h
> @@ -160,6 +160,7 @@ enum rq_flag_bits {
> __REQ_FLUSH_SEQ, /* request for flush sequence */
> __REQ_IO_STAT, /* account I/O stat */
> __REQ_MIXED_MERGE, /* merge of different types, fail separately */
> + __REQ_PM, /* runtime pm request */
> __REQ_NR_BITS, /* stops here */
> };
>
> @@ -201,5 +202,6 @@ enum rq_flag_bits {
> #define REQ_IO_STAT (1 << __REQ_IO_STAT)
> #define REQ_MIXED_MERGE (1 << __REQ_MIXED_MERGE)
> #define REQ_SECURE (1 << __REQ_SECURE)
> +#define REQ_PM (1 << __REQ_PM)
>
> #endif /* __LINUX_BLK_TYPES_H */
> diff --git a/include/scsi/scsi_device.h b/include/scsi/scsi_device.h
> index ba96988..e7fdff5 100644
> --- a/include/scsi/scsi_device.h
> +++ b/include/scsi/scsi_device.h
> @@ -388,6 +388,10 @@ extern int scsi_execute_req(struct scsi_device *sdev, const unsigned char *cmd,
> int data_direction, void *buffer, unsigned bufflen,
> struct scsi_sense_hdr *, int timeout, int retries,
> int *resid);
> +extern int scsi_execute_req_flag(struct scsi_device *sdev, const unsigned char *cmd,
> + int data_direction, void *buffer, unsigned bufflen,
> + struct scsi_sense_hdr *, int timeout, int retries,
> + int *resid, int flags);
>
> #ifdef CONFIG_PM_RUNTIME
> extern int scsi_autopm_get_device(struct scsi_device *);
>



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