mmc: cqhci: fix space allocated for transfer descriptor [Linux 5.0]

mmc: cqhci: fix space allocated for transfer descriptor [Linux 5.0]

This Linux kernel change "mmc: cqhci: fix space allocated for transfer descriptor" is included in the Linux 5.0 release. This change is authored by Alamy Liu <alamy.liu [at]> on Mon Feb 25 11:22:13 2019 -0800. The commit for this change in Linux stable tree is 27ec9dc (patch).

mmc: cqhci: fix space allocated for transfer descriptor

There is not enough space being allocated when DCMD is disabled.

CQE_DCMD is not necessary to be enabled when CQE is enabled.
(Software could halt CQE to send command)

In the case that CQE_DCMD is not enabled, it still needs to allocate
space for data transfer. For instance:
  CQE_DCMD is enabled:  31 slots space (one slot used by DCMD)
  CQE_DCMD is disabled: 32 slots space

Fixes: a4080225f51d ("mmc: cqhci: support for command queue enabled host")
Signed-off-by: Alamy Liu <[email protected]>
Acked-by: Adrian Hunter <[email protected]>
Cc: [email protected]
Signed-off-by: Ulf Hansson <[email protected]>

There are 2 lines of Linux source code added/deleted in this change. Code changes to Linux kernel are as follows.

 drivers/mmc/host/cqhci.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/mmc/host/cqhci.c b/drivers/mmc/host/cqhci.c
index 159270e..bd9a59b 100644
--- a/drivers/mmc/host/cqhci.c
+++ b/drivers/mmc/host/cqhci.c
@@ -201,7 +201,7 @@ static int cqhci_host_alloc_tdl(struct cqhci_host *cq_host)
    cq_host->desc_size = cq_host->slot_sz * cq_host->num_slots;

    cq_host->data_size = cq_host->trans_desc_len * cq_host->mmc->max_segs *
-       (cq_host->num_slots - 1);
+       cq_host->mmc->cqe_qdepth;

    pr_debug("%s: cqhci: desc_size: %zu data_sz: %zu slot-sz: %d\n",
         mmc_hostname(cq_host->mmc), cq_host->desc_size, cq_host->data_size,

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