On 09/15/2014 12:36 PM, Ching Huang wrote: > On Mon, 2014-09-15 at 12:25 +0200, Tomas Henzl wrote: >> On 09/15/2014 04:56 AM, Ching Huang wrote: >>> On Fri, 2014-09-12 at 15:34 +0200, Tomas Henzl wrote: >>>> On 09/12/2014 09:29 AM, Ching Huang wrote: >>>>> From: Ching Huang <ching2048@xxxxxxxxxxxx> >>>>> >>>>> This patch is to modify previous patch 13/17 and it is relative to >>>>> http://git.infradead.org/users/hch/scsi-queue.git/tree/arcmsr-for-3.18:/drivers/scsi/arcmsr >>>>> >>>>> change in v4: >>>>> 1. for readability, rename firstindex to getIndex, rename lastindex to putIndex >>>> For some reason, the names head+tail areusual for a circular buffer. >>>> But let us ignore the names, I don't care. >>>>> 2. define ARCMSR_API_DATA_BUFLEN as 1032 >>>>> 3. simplify ioctl data read by macro CIRC_CNT_TO_END and CIRC_CNT >>>> It's definitely better when you post renames and other non-functional changes in separate >>>> patches, it's easier for the reviewer. >>>>> Signed-off-by: Ching Huang <ching2048@xxxxxxxxxxxx> >>>>> --- >>>>> >>>>> diff -uprN a/drivers/scsi/arcmsr/arcmsr_attr.c b/drivers/scsi/arcmsr/arcmsr_attr.c >>>>> --- a/drivers/scsi/arcmsr/arcmsr_attr.c 2014-08-21 12:14:27.000000000 +0800 >>>>> +++ b/drivers/scsi/arcmsr/arcmsr_attr.c 2014-09-12 15:18:46.659125000 +0800 >>>>> @@ -50,6 +50,7 @@ >>>>> #include <linux/errno.h> >>>>> #include <linux/delay.h> >>>>> #include <linux/pci.h> >>>>> +#include <linux/circ_buf.h> >>>>> >>>>> #include <scsi/scsi_cmnd.h> >>>>> #include <scsi/scsi_device.h> >>>>> @@ -68,7 +69,7 @@ static ssize_t arcmsr_sysfs_iop_message_ >>>>> struct device *dev = container_of(kobj,struct device,kobj); >>>>> struct Scsi_Host *host = class_to_shost(dev); >>>>> struct AdapterControlBlock *acb = (struct AdapterControlBlock *) host->hostdata; >>>>> - uint8_t *pQbuffer,*ptmpQbuffer; >>>>> + uint8_t *ptmpQbuffer; >>>>> int32_t allxfer_len = 0; >>>>> unsigned long flags; >>>>> >>>>> @@ -78,57 +79,22 @@ static ssize_t arcmsr_sysfs_iop_message_ >>>>> /* do message unit read. */ >>>>> ptmpQbuffer = (uint8_t *)buf; >>>>> spin_lock_irqsave(&acb->rqbuffer_lock, flags); >>>>> - if (acb->rqbuf_firstindex != acb->rqbuf_lastindex) { >>>>> - pQbuffer = &acb->rqbuffer[acb->rqbuf_firstindex]; >>>>> - if (acb->rqbuf_firstindex > acb->rqbuf_lastindex) { >>>>> - if ((ARCMSR_MAX_QBUFFER - acb->rqbuf_firstindex) >= 1032) { >>>>> - memcpy(ptmpQbuffer, pQbuffer, 1032); >>>>> - acb->rqbuf_firstindex += 1032; >>>>> - acb->rqbuf_firstindex %= ARCMSR_MAX_QBUFFER; >>>>> - allxfer_len = 1032; >>>>> - } else { >>>>> - if (((ARCMSR_MAX_QBUFFER - acb->rqbuf_firstindex) >>>>> - + acb->rqbuf_lastindex) > 1032) { >>>>> - memcpy(ptmpQbuffer, pQbuffer, >>>>> - ARCMSR_MAX_QBUFFER >>>>> - - acb->rqbuf_firstindex); >>>>> - ptmpQbuffer += ARCMSR_MAX_QBUFFER >>>>> - - acb->rqbuf_firstindex; >>>>> - memcpy(ptmpQbuffer, acb->rqbuffer, 1032 >>>>> - - (ARCMSR_MAX_QBUFFER - >>>>> - acb->rqbuf_firstindex)); >>>>> - acb->rqbuf_firstindex = 1032 - >>>>> - (ARCMSR_MAX_QBUFFER - >>>>> - acb->rqbuf_firstindex); >>>>> - allxfer_len = 1032; >>>>> - } else { >>>>> - memcpy(ptmpQbuffer, pQbuffer, >>>>> - ARCMSR_MAX_QBUFFER - >>>>> - acb->rqbuf_firstindex); >>>>> - ptmpQbuffer += ARCMSR_MAX_QBUFFER - >>>>> - acb->rqbuf_firstindex; >>>>> - memcpy(ptmpQbuffer, acb->rqbuffer, >>>>> - acb->rqbuf_lastindex); >>>>> - allxfer_len = ARCMSR_MAX_QBUFFER - >>>>> - acb->rqbuf_firstindex + >>>>> - acb->rqbuf_lastindex; >>>>> - acb->rqbuf_firstindex = >>>>> - acb->rqbuf_lastindex; >>>>> - } >>>>> - } >>>>> - } else { >>>>> - if ((acb->rqbuf_lastindex - acb->rqbuf_firstindex) > 1032) { >>>>> - memcpy(ptmpQbuffer, pQbuffer, 1032); >>>>> - acb->rqbuf_firstindex += 1032; >>>>> - allxfer_len = 1032; >>>>> - } else { >>>>> - memcpy(ptmpQbuffer, pQbuffer, acb->rqbuf_lastindex >>>>> - - acb->rqbuf_firstindex); >>>>> - allxfer_len = acb->rqbuf_lastindex - >>>>> - acb->rqbuf_firstindex; >>>>> - acb->rqbuf_firstindex = acb->rqbuf_lastindex; >>>>> - } >>>>> + if (acb->rqbuf_getIndex != acb->rqbuf_putIndex) { >>>>> + unsigned int tail = acb->rqbuf_getIndex; >>>>> + unsigned int head = acb->rqbuf_putIndex; >>>>> + unsigned int cnt_to_end = CIRC_CNT_TO_END(head, tail, ARCMSR_MAX_QBUFFER); >>>>> + >>>>> + allxfer_len = CIRC_CNT(head, tail, ARCMSR_MAX_QBUFFER); >>>>> + if (allxfer_len > ARCMSR_API_DATA_BUFLEN) >>>>> + allxfer_len = ARCMSR_API_DATA_BUFLEN; >>>>> + >>>>> + if (allxfer_len <= cnt_to_end) >>>>> + memcpy(ptmpQbuffer, acb->rqbuffer + tail, allxfer_len); >>>>> + else { >>>>> + memcpy(ptmpQbuffer, acb->rqbuffer + tail, cnt_to_end); >>>>> + memcpy(ptmpQbuffer + cnt_to_end, acb->rqbuffer, allxfer_len - cnt_to_end); >>>>> } >>>>> + acb->rqbuf_getIndex = (acb->rqbuf_getIndex + allxfer_len) % ARCMSR_MAX_QBUFFER; >>>>> } >>>>> if (acb->acb_flags & ACB_F_IOPDATA_OVERFLOW) { >>>>> struct QBUFFER __iomem *prbuffer; >>>>> @@ -150,33 +116,32 @@ static ssize_t arcmsr_sysfs_iop_message_ >>>>> struct device *dev = container_of(kobj,struct device,kobj); >>>>> struct Scsi_Host *host = class_to_shost(dev); >>>>> struct AdapterControlBlock *acb = (struct AdapterControlBlock *) host->hostdata; >>>>> - int32_t my_empty_len, user_len, wqbuf_firstindex, wqbuf_lastindex; >>>>> + int32_t my_empty_len, user_len, wqbuf_getIndex, wqbuf_putIndex; >>>>> uint8_t *pQbuffer, *ptmpuserbuffer; >>>>> unsigned long flags; >>>>> >>>>> if (!capable(CAP_SYS_ADMIN)) >>>>> return -EACCES; >>>>> - if (count > 1032) >>>>> + if (count > ARCMSR_API_DATA_BUFLEN) >>>>> return -EINVAL; >>>>> /* do message unit write. */ >>>>> ptmpuserbuffer = (uint8_t *)buf; >>>>> user_len = (int32_t)count; >>>>> spin_lock_irqsave(&acb->wqbuffer_lock, flags); >>>>> - wqbuf_lastindex = acb->wqbuf_lastindex; >>>>> - wqbuf_firstindex = acb->wqbuf_firstindex; >>>>> - if (wqbuf_lastindex != wqbuf_firstindex) { >>>>> + wqbuf_putIndex = acb->wqbuf_putIndex; >>>>> + wqbuf_getIndex = acb->wqbuf_getIndex; >>>>> + if (wqbuf_putIndex != wqbuf_getIndex) { >>>>> arcmsr_write_ioctldata2iop(acb); >>>>> spin_unlock_irqrestore(&acb->wqbuffer_lock, flags); >>>>> return 0; /*need retry*/ >>>>> } else { >>>>> - my_empty_len = (wqbuf_firstindex-wqbuf_lastindex - 1) >>>>> - &(ARCMSR_MAX_QBUFFER - 1); >>>>> + my_empty_len = ARCMSR_MAX_QBUFFER - 1; >>>> This^ doesn't look like like an rename can you explain? >>> It is just a code simplification. >> Yes it is of some kind. But I think it's also a bug, because you have replaced >> 'firstindex - lastindex' with nothing. > It will be not a bug. At here, firstindex == lastindex, so firstindex-lastindex is 0 Thanks, I haven't seen it before. In that case because user_len is max 1032 and ARCMSR_MAX_QBUFFER is 4k the next if statement '(my_empty_len >= user_len)' will be true for any user_len (<1032), and it looks like you could remove my_empty_len completely. >>>> Let us stop here, or we end in an endless loop of corrections. The original 13/17 >>>> you are trying to improve here was at least without bugs (better said I haven't noticed) so >>>> improving it now only complicates the process. >>>> My suggestion is -let us skip this patch and focus only on fixing the spinlock problem found in 16/17. >>>> OKay? >>> Agree. >>>> Cheers, >>>> Tomas >>>> >>> -- >>> To unsubscribe from this list: send the line "unsubscribe linux-scsi" in >>> the body of a message to majordomo@xxxxxxxxxxxxxxx >>> More majordomo info at http://vger.kernel.org/majordomo-info.html > > -- > To unsubscribe from this list: send the line "unsubscribe linux-scsi" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
