Instead of setting up a kernel pointer to track the current PIO address,
track the offset in the current page, and do an atomic kmap for the page
while doing the actual PIO operations.

Signed-off-by: Christoph Hellwig <h...@lst.de>
---
 drivers/mmc/host/sh_mmcif.c | 59 +++++++++++++++++++++++--------------
 1 file changed, 37 insertions(+), 22 deletions(-)

diff --git a/drivers/mmc/host/sh_mmcif.c b/drivers/mmc/host/sh_mmcif.c
index 81bd9afb0980..24c3f13bafdb 100644
--- a/drivers/mmc/host/sh_mmcif.c
+++ b/drivers/mmc/host/sh_mmcif.c
@@ -228,7 +228,7 @@ struct sh_mmcif_host {
        bool dying;
        long timeout;
        void __iomem *addr;
-       u32 *pio_ptr;
+       u32 pio_offset;
        spinlock_t lock;                /* protect sh_mmcif_host::state */
        enum sh_mmcif_state state;
        enum sh_mmcif_wait_for wait_for;
@@ -595,7 +595,7 @@ static int sh_mmcif_error_manage(struct sh_mmcif_host *host)
        return ret;
 }
 
-static bool sh_mmcif_next_block(struct sh_mmcif_host *host, u32 *p)
+static bool sh_mmcif_next_block(struct sh_mmcif_host *host)
 {
        struct mmc_data *data = host->mrq->data;
 
@@ -606,10 +606,10 @@ static bool sh_mmcif_next_block(struct sh_mmcif_host 
*host, u32 *p)
 
        if (host->sg_blkidx == data->sg->length) {
                host->sg_blkidx = 0;
-               if (++host->sg_idx < data->sg_len)
-                       host->pio_ptr = sg_virt(++data->sg);
-       } else {
-               host->pio_ptr = p;
+               if (++host->sg_idx < data->sg_len) {
+                       data->sg++;
+                       host->pio_offset = data->sg->offset / 4;
+               }
        }
 
        return host->sg_idx != data->sg_len;
@@ -631,8 +631,8 @@ static bool sh_mmcif_read_block(struct sh_mmcif_host *host)
 {
        struct device *dev = sh_mmcif_host_to_dev(host);
        struct mmc_data *data = host->mrq->data;
-       u32 *p = sg_virt(data->sg);
-       int i;
+       u32 *p;
+       int off, i;
 
        if (host->sd_error) {
                data->error = sh_mmcif_error_manage(host);
@@ -640,8 +640,11 @@ static bool sh_mmcif_read_block(struct sh_mmcif_host *host)
                return false;
        }
 
+       p = sg_kmap_atomic(data->sg);
+       off = data->sg->offset / 4;
        for (i = 0; i < host->blocksize / 4; i++)
-               *p++ = sh_mmcif_readl(host->addr, MMCIF_CE_DATA);
+               p[off++] = sh_mmcif_readl(host->addr, MMCIF_CE_DATA);
+       sg_kunmap_atomic(data->sg, p);
 
        /* buffer read end */
        sh_mmcif_bitset(host, MMCIF_CE_INT_MASK, MASK_MBUFRE);
@@ -664,7 +667,7 @@ static void sh_mmcif_multi_read(struct sh_mmcif_host *host,
        host->wait_for = MMCIF_WAIT_FOR_MREAD;
        host->sg_idx = 0;
        host->sg_blkidx = 0;
-       host->pio_ptr = sg_virt(data->sg);
+       host->pio_offset = data->sg->offset / 4;
 
        sh_mmcif_bitset(host, MMCIF_CE_INT_MASK, MASK_MBUFREN);
 }
@@ -673,7 +676,7 @@ static bool sh_mmcif_mread_block(struct sh_mmcif_host *host)
 {
        struct device *dev = sh_mmcif_host_to_dev(host);
        struct mmc_data *data = host->mrq->data;
-       u32 *p = host->pio_ptr;
+       u32 *p;
        int i;
 
        if (host->sd_error) {
@@ -684,10 +687,14 @@ static bool sh_mmcif_mread_block(struct sh_mmcif_host 
*host)
 
        BUG_ON(!data->sg->length);
 
-       for (i = 0; i < host->blocksize / 4; i++)
-               *p++ = sh_mmcif_readl(host->addr, MMCIF_CE_DATA);
+       p = sg_kmap_atomic(data->sg);
+       for (i = 0; i < host->blocksize / 4; i++) {
+               p[host->pio_offset++] =
+                       sh_mmcif_readl(host->addr, MMCIF_CE_DATA);
+       }
+       sg_kunmap_atomic(data->sg, p);
 
-       if (!sh_mmcif_next_block(host, p))
+       if (!sh_mmcif_next_block(host))
                return false;
 
        sh_mmcif_bitset(host, MMCIF_CE_INT_MASK, MASK_MBUFREN);
@@ -711,8 +718,8 @@ static bool sh_mmcif_write_block(struct sh_mmcif_host *host)
 {
        struct device *dev = sh_mmcif_host_to_dev(host);
        struct mmc_data *data = host->mrq->data;
-       u32 *p = sg_virt(data->sg);
-       int i;
+       u32 *p;
+       int off, i;
 
        if (host->sd_error) {
                data->error = sh_mmcif_error_manage(host);
@@ -720,8 +727,11 @@ static bool sh_mmcif_write_block(struct sh_mmcif_host 
*host)
                return false;
        }
 
+       p = sg_kmap_atomic(data->sg);
+       off = data->sg->offset / 4;
        for (i = 0; i < host->blocksize / 4; i++)
-               sh_mmcif_writel(host->addr, MMCIF_CE_DATA, *p++);
+               sh_mmcif_writel(host->addr, MMCIF_CE_DATA, p[off++]);
+       sg_kunmap_atomic(data->sg, p);
 
        /* buffer write end */
        sh_mmcif_bitset(host, MMCIF_CE_INT_MASK, MASK_MDTRANE);
@@ -744,7 +754,7 @@ static void sh_mmcif_multi_write(struct sh_mmcif_host *host,
        host->wait_for = MMCIF_WAIT_FOR_MWRITE;
        host->sg_idx = 0;
        host->sg_blkidx = 0;
-       host->pio_ptr = sg_virt(data->sg);
+       host->pio_offset = data->sg->offset / 4;
 
        sh_mmcif_bitset(host, MMCIF_CE_INT_MASK, MASK_MBUFWEN);
 }
@@ -753,7 +763,7 @@ static bool sh_mmcif_mwrite_block(struct sh_mmcif_host 
*host)
 {
        struct device *dev = sh_mmcif_host_to_dev(host);
        struct mmc_data *data = host->mrq->data;
-       u32 *p = host->pio_ptr;
+       u32 *p;
        int i;
 
        if (host->sd_error) {
@@ -764,10 +774,14 @@ static bool sh_mmcif_mwrite_block(struct sh_mmcif_host 
*host)
 
        BUG_ON(!data->sg->length);
 
-       for (i = 0; i < host->blocksize / 4; i++)
-               sh_mmcif_writel(host->addr, MMCIF_CE_DATA, *p++);
+       p = sg_kmap_atomic(data->sg);
+       for (i = 0; i < host->blocksize / 4; i++) {
+               sh_mmcif_writel(host->addr, MMCIF_CE_DATA,
+                               p[host->pio_offset++]);
+       }
+       sg_kunmap_atomic(data->sg, p);
 
-       if (!sh_mmcif_next_block(host, p))
+       if (!sh_mmcif_next_block(host))
                return false;
 
        sh_mmcif_bitset(host, MMCIF_CE_INT_MASK, MASK_MBUFWEN);
@@ -1424,6 +1438,7 @@ static int sh_mmcif_probe(struct platform_device *pdev)
        spin_lock_init(&host->lock);
 
        mmc->ops = &sh_mmcif_ops;
+       mmc->need_kmap = 1;
        sh_mmcif_init_ocr(host);
 
        mmc->caps |= MMC_CAP_MMC_HIGHSPEED | MMC_CAP_WAIT_WHILE_BUSY;
-- 
2.20.1

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