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. >> 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
