ps3flash: Always read chunks of 256 KiB, and cache them

Signed-off-by: Geert Uytterhoeven <Geert.Uytterhoeven@sonycom.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

1 files changed, 17 insertions, 30 deletions

diff --git a/drivers/char/ps3flash.c b/drivers/char/ps3flash.c
index d884d31491d2..f424d394a286 100644
--- a/drivers/char/ps3flash.c
+++ b/drivers/char/ps3flash.c
@@ -41,10 +41,11 @@ struct ps3flash_private {
 static struct ps3_storage_device *ps3flash_dev;
 
 static int ps3flash_read_write_sectors(struct ps3_storage_device *dev,
-                                       u64 lpar, u64 start_sector, u64 sectors,
-                                       int write)
+                                       u64 start_sector, int write)
 {
-        u64 res = ps3stor_read_write_sectors(dev, lpar, start_sector, sectors,
+        struct ps3flash_private *priv = ps3_system_bus_get_drvdata(&dev->sbd);
+        u64 res = ps3stor_read_write_sectors(dev, dev->bounce_lpar,
+                                             start_sector, priv->chunk_sectors,
                                              write);
         if (res) {
                 dev_err(&dev->sbd.core, "%s:%u: %s failed 0x%llx\n", __func__,
@@ -62,8 +63,7 @@ static int ps3flash_writeback(struct ps3_storage_device *dev)
         if (!priv->dirty || priv->tag < 0)
                 return 0;
 
-        res = ps3flash_read_write_sectors(dev, dev->bounce_lpar, priv->tag,
-                                          priv->chunk_sectors, 1);
+        res = ps3flash_read_write_sectors(dev, priv->tag, 1);
         if (res)
                 return res;
 
@@ -71,17 +71,12 @@ static int ps3flash_writeback(struct ps3_storage_device *dev)
         return 0;
 }
 
-static int ps3flash_fetch(struct ps3_storage_device *dev, u64 start_sector,
-                          u64 sectors)
+static int ps3flash_fetch(struct ps3_storage_device *dev, u64 start_sector)
 {
         struct ps3flash_private *priv = ps3_system_bus_get_drvdata(&dev->sbd);
-        unsigned int tag, offset;
-        u64 lpar;
         int res;
 
-        offset = start_sector % priv->chunk_sectors;
-        tag = start_sector - offset;
-        if (tag == priv->tag)
+        if (start_sector == priv->tag)
                 return 0;
 
         res = ps3flash_writeback(dev);
@@ -90,15 +85,11 @@ static int ps3flash_fetch(struct ps3_storage_device *dev, u64 start_sector,
 
         priv->tag = -1;
 
-        lpar = dev->bounce_lpar + offset * dev->blk_size;
-        res = ps3flash_read_write_sectors(dev, lpar, start_sector, sectors, 0);
+        res = ps3flash_read_write_sectors(dev, start_sector, 0);
         if (res)
                 return res;
 
-        /* We don't bother caching reads smaller than the chunk size */
-        if (sectors == priv->chunk_sectors)
-                priv->tag = tag;
-
+        priv->tag = start_sector;
         return 0;
 }
 
@@ -134,7 +125,7 @@ static ssize_t ps3flash_read(char __user *userbuf, void *kernelbuf,
 {
         struct ps3_storage_device *dev = ps3flash_dev;
         struct ps3flash_private *priv = ps3_system_bus_get_drvdata(&dev->sbd);
-        u64 size, start_sector, end_sector, offset, sectors;
+        u64 size, sector, offset;
         int res;
         size_t remaining, n;
         const void *src;
@@ -154,24 +145,20 @@ static ssize_t ps3flash_read(char __user *userbuf, void *kernelbuf,
                 count = size - *pos;
         }
 
-        start_sector = *pos / dev->blk_size;
+        sector = *pos / dev->bounce_size * priv->chunk_sectors;
         offset = *pos % dev->bounce_size;
-        end_sector = DIV_ROUND_UP(*pos + count, dev->blk_size);
 
         remaining = count;
         do {
-                sectors = min(end_sector - start_sector,
-                              priv->chunk_sectors -
-                              start_sector % priv->chunk_sectors);
+                n = min_t(u64, remaining, dev->bounce_size - offset);
+                src = dev->bounce_buf + offset;
 
                 mutex_lock(&priv->mutex);
 
-                res = ps3flash_fetch(dev, start_sector, sectors);
+                res = ps3flash_fetch(dev, sector);
                 if (res)
                         goto fail;
 
-                n = min_t(u64, remaining, dev->bounce_size - offset);
-                src = dev->bounce_buf + offset;
                 dev_dbg(&dev->sbd.core,
                         "%s:%u: copy %lu bytes from 0x%p to U0x%p/K0x%p\n",
                         __func__, __LINE__, n, src, userbuf, kernelbuf);
@@ -191,7 +178,7 @@ static ssize_t ps3flash_read(char __user *userbuf, void *kernelbuf,
 
                 *pos += n;
                 remaining -= n;
-                start_sector += sectors;
+                sector += priv->chunk_sectors;
                 offset = 0;
         } while (remaining > 0);
 
@@ -233,17 +220,17 @@ static ssize_t ps3flash_write(const char __user *userbuf,
         remaining = count;
         do {
                 n = min_t(u64, remaining, dev->bounce_size - offset);
+                dst = dev->bounce_buf + offset;
 
                 mutex_lock(&priv->mutex);
 
                 if (n != dev->bounce_size)
-                        res = ps3flash_fetch(dev, sector, priv->chunk_sectors);
+                        res = ps3flash_fetch(dev, sector);
                 else if (sector != priv->tag)
                         res = ps3flash_writeback(dev);
                 if (res)
                         goto fail;
 
-                dst = dev->bounce_buf + offset;
                 dev_dbg(&dev->sbd.core,
                         "%s:%u: copy %lu bytes from U0x%p/K0x%p to 0x%p\n",
                         __func__, __LINE__, n, userbuf, kernelbuf, dst);