scsi: arcmsr: Fix reading empty buffer length

Fix empty buffer length error which causes ARECA CLI app command timeout.

Signed-off-by: ching Huang <ching2048@areca.com.tw>
Link: https://lore.kernel.org/r/4aec4385abc6eab10b575c28130ec615a144492d.camel@areca.com.tw
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

diff --git a/drivers/scsi/arcmsr/arcmsr_hba.c b/drivers/scsi/arcmsr/arcmsr_hba.c
index ce92d4281da6f600a9709414d798c3ddbbe993aa..f97936d66a6a1b4ba35d78a70ad5860db578b163 100644 (file)
--- a/drivers/scsi/arcmsr/arcmsr_hba.c
+++ b/drivers/scsi/arcmsr/arcmsr_hba.c
@@ -2255,8 +2255,11 @@ static void arcmsr_iop2drv_data_wrote_handle(struct AdapterControlBlock *acb)
 
        spin_lock_irqsave(&acb->rqbuffer_lock, flags);
        prbuffer = arcmsr_get_iop_rqbuffer(acb);
-       buf_empty_len = (acb->rqbuf_putIndex - acb->rqbuf_getIndex - 1) &
-               (ARCMSR_MAX_QBUFFER - 1);
+       if (acb->rqbuf_putIndex >= acb->rqbuf_getIndex) {
+               buf_empty_len = (ARCMSR_MAX_QBUFFER - 1) -
+               (acb->rqbuf_putIndex - acb->rqbuf_getIndex);
+       } else
+               buf_empty_len = acb->rqbuf_getIndex - acb->rqbuf_putIndex - 1;
        if (buf_empty_len >= readl(&prbuffer->data_len)) {
                if (arcmsr_Read_iop_rqbuffer_data(acb, prbuffer) == 0)
                        acb->acb_flags |= ACB_F_IOPDATA_OVERFLOW;