scsi: storvsc: Fix max_outstanding_req_per_channel for Win8 and newer
Current code overestimates the value of max_outstanding_req_per_channel for Win8 and newer hosts, since vmscsi_size_delta is set to the initial value of sizeof(vmscsi_win8_extension) rather than zero. This may lead to wrong decisions when using ring_avail_percent_lowater equals to zero. The estimate of max_outstanding_req_per_channel is 'exact' for Win7 and older hosts. A better choice, keeping the algorithm for the estimation simple, is to err the other way around, i.e., to underestimate for Win7 and older but to use the exact value for Win8 and newer. Link: https://lore.kernel.org/r/20201217203321.4539-2-parri.andrea@gmail.com Cc: "James E.J. Bottomley" <jejb@linux.ibm.com> Cc: "Martin K. Petersen" <martin.petersen@oracle.com> Cc: linux-scsi@vger.kernel.org Suggested-by:Dexuan Cui <decui@microsoft.com> Reviewed-by:
Dexuan Cui <decui@microsoft.com> Reviewed-by:
Michael Kelley <mikelley@microsoft.com> Signed-off-by:
Andrea Parri (Microsoft) <parri.andrea@gmail.com> Signed-off-by:
Martin K. Petersen <martin.petersen@oracle.com>
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181dd9a4
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