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 > > >> 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
