Re: [PATCH V1] mmc: mmc_test: Pass different sg lists for non-blocking requests

From: Adrian Hunter
Date: Tue Feb 18 2020 - 03:56:22 EST


On 11/02/20 11:36 am, Veerabhadrarao Badiganti wrote:
> Supply a separate sg list for each of the request in non-blocking
> IO test cases where two requests will be issued at same time.
>
> Otherwise, sg memory may get unmapped when a request is done while
> same memory is being accessed by controller from the other request,
> and it leads to iommu errors with below call stack:
>
> __arm_lpae_unmap+0x2e0/0x478
> arm_lpae_unmap+0x54/0x70
> arm_smmu_unmap+0x64/0xa4
> __iommu_unmap+0xb8/0x1f0
> iommu_unmap_fast+0x38/0x48
> __iommu_dma_unmap+0x88/0x108
> iommu_dma_unmap_sg+0x90/0xa4
> sdhci_post_req+0x5c/0x78
> mmc_test_start_areq+0x10c/0x120 [mmc_test]
> mmc_test_area_io_seq+0x150/0x264 [mmc_test]
> mmc_test_rw_multiple+0x174/0x1c0 [mmc_test]
> mmc_test_rw_multiple_sg_len+0x44/0x6c [mmc_test]
> mmc_test_profile_sglen_wr_nonblock_perf+0x6c/0x94 [mmc_test]
> mtf_test_write+0x238/0x3cc [mmc_test]
>
> Signed-off-by: Veerabhadrarao Badiganti <vbadigan@xxxxxxxxxxxxxx>
> ---
> drivers/mmc/core/mmc_test.c | 38 ++++++++++++++++++++++++++++++++------
> 1 file changed, 32 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/mmc/core/mmc_test.c b/drivers/mmc/core/mmc_test.c
> index 492dd45..69bdf60 100644
> --- a/drivers/mmc/core/mmc_test.c
> +++ b/drivers/mmc/core/mmc_test.c
> @@ -71,6 +71,7 @@ struct mmc_test_mem {
> * @sg_len: length of currently mapped scatterlist @sg
> * @mem: allocated memory
> * @sg: scatterlist
> + * @sg_areq: scatterlist for non blocking request
> */
> struct mmc_test_area {
> unsigned long max_sz;
> @@ -82,6 +83,7 @@ struct mmc_test_area {
> unsigned int sg_len;
> struct mmc_test_mem *mem;
> struct scatterlist *sg;
> + struct scatterlist *sg_areq;
> };
>
> /**
> @@ -836,7 +838,9 @@ static int mmc_test_start_areq(struct mmc_test_card *test,
> }
>
> static int mmc_test_nonblock_transfer(struct mmc_test_card *test,
> - struct scatterlist *sg, unsigned sg_len,
> + struct scatterlist *sg,
> + struct scatterlist *sg_areq,
> + unsigned int sg_len,
> unsigned dev_addr, unsigned blocks,
> unsigned blksz, int write, int count)
> {
> @@ -867,6 +871,7 @@ static int mmc_test_nonblock_transfer(struct mmc_test_card *test,
> prev_mrq = &rq2->mrq;
>
> swap(mrq, prev_mrq);
> + swap(sg, sg_areq);
> dev_addr += blocks;
> }
>
> @@ -1396,7 +1401,7 @@ static int mmc_test_no_highmem(struct mmc_test_card *test)
> * Map sz bytes so that it can be transferred.
> */
> static int mmc_test_area_map(struct mmc_test_card *test, unsigned long sz,
> - int max_scatter, int min_sg_len)
> + int max_scatter, int min_sg_len, bool nonblock)
> {
> struct mmc_test_area *t = &test->area;
> int err;
> @@ -1411,6 +1416,20 @@ static int mmc_test_area_map(struct mmc_test_card *test, unsigned long sz,
> err = mmc_test_map_sg(t->mem, sz, t->sg, 1, t->max_segs,
> t->max_seg_sz, &t->sg_len, min_sg_len);
> }
> +
> + if (err || !nonblock)
> + goto err;
> +
> + if (max_scatter) {
> + err = mmc_test_map_sg_max_scatter(t->mem, sz, t->sg_areq,
> + t->max_segs, t->max_seg_sz,
> + &t->sg_len);
> + } else {
> + err = mmc_test_map_sg(t->mem, sz, t->sg_areq, 1, t->max_segs,
> + t->max_seg_sz, &t->sg_len, min_sg_len);
> + }

I suggest getting the length to a local and confirming it is the same

+ if (max_scatter) {
+ err = mmc_test_map_sg_max_scatter(t->mem, sz, t->sg_areq,
+ t->max_segs, t->max_seg_sz,
+ &sg_len);
+ } else {
+ err = mmc_test_map_sg(t->mem, sz, t->sg_areq, 1, t->max_segs,
+ t->max_seg_sz, &sg_len, min_sg_len);
+ }
+ if (!err && sg_len != t->sg_len)
+ err = -EINVAL;

> +
> +err:
> if (err)
> pr_info("%s: Failed to map sg list\n",
> mmc_hostname(test->card->host));
> @@ -1458,15 +1477,16 @@ static int mmc_test_area_io_seq(struct mmc_test_card *test, unsigned long sz,
> sz = max_tfr;
> }
>
> - ret = mmc_test_area_map(test, sz, max_scatter, min_sg_len);
> + ret = mmc_test_area_map(test, sz, max_scatter, min_sg_len, nonblock);
> if (ret)
> return ret;
>
> if (timed)
> ktime_get_ts64(&ts1);
> if (nonblock)
> - ret = mmc_test_nonblock_transfer(test, t->sg, t->sg_len,
> - dev_addr, t->blocks, 512, write, count);
> + ret = mmc_test_nonblock_transfer(test, t->sg, t->sg_areq,
> + t->sg_len, dev_addr, t->blocks, 512, write,
> + count);
> else
> for (i = 0; i < count && ret == 0; i++) {
> ret = mmc_test_area_transfer(test, dev_addr, write);
> @@ -1584,6 +1604,12 @@ static int mmc_test_area_init(struct mmc_test_card *test, int erase, int fill)
> goto out_free;
> }
>
> + t->sg_areq = kmalloc_array(t->max_segs, sizeof(*t->sg), GFP_KERNEL);

Needs to be freed in mmc_test_area_cleanup()

> + if (!t->sg_areq) {
> + ret = -ENOMEM;
> + goto out_free;
> + }
> +
> t->dev_addr = mmc_test_capacity(test->card) / 2;
> t->dev_addr -= t->dev_addr % (t->max_sz >> 9);
>
> @@ -2468,7 +2494,7 @@ static int __mmc_test_cmds_during_tfr(struct mmc_test_card *test,
> if (!(test->card->host->caps & MMC_CAP_CMD_DURING_TFR))
> return RESULT_UNSUP_HOST;
>
> - ret = mmc_test_area_map(test, sz, 0, 0);
> + ret = mmc_test_area_map(test, sz, 0, 0, use_areq);
> if (ret)
> return ret;
>
>