ps3: Replace direct file operations by callback

Currently the FLASH database is updated by the kernel using file operations,
meant for userspace only. While this works for us because copy_{from,to}_user()
on powerpc can handle kernel pointers, this is unportable and a bad example.
Replace the file operations by callbacks, registered by the ps3flash driver.

Signed-off-by: Geert Uytterhoeven <Geert.Uytterhoeven@sonycom.com>
Cc: Geoff Levand <geoffrey.levand@am.sony.com>
Acked-by: Geoff Levand <geoffrey.levand@am.sony.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

1 files changed, 70 insertions, 24 deletions

diff --git a/drivers/char/ps3flash.c b/drivers/char/ps3flash.c
index 184e6ed2393d..f7f21f47ea02 100644
--- a/drivers/char/ps3flash.c
+++ b/drivers/char/ps3flash.c
@@ -104,18 +104,19 @@ out:
         return res;
 }
 
-static ssize_t ps3flash_read(struct file *file, char __user *buf, size_t count,
-                             loff_t *pos)
+static ssize_t ps3flash_read(char __user *userbuf, void *kernelbuf,
+                             size_t count, loff_t *pos)
 {
         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;
         ssize_t sectors_read;
         size_t remaining, n;
+        const void *src;
 
         dev_dbg(&dev->sbd.core,
-                "%s:%u: Reading %zu bytes at position %lld to user 0x%p\n",
-                __func__, __LINE__, count, *pos, buf);
+                "%s:%u: Reading %zu bytes at position %lld to U0x%p/K0x%p\n",
+                __func__, __LINE__, count, *pos, userbuf, kernelbuf);
 
         size = dev->regions[dev->region_idx].size*dev->blk_size;
         if (*pos >= size || !count)
@@ -145,19 +146,26 @@ static ssize_t ps3flash_read(struct file *file, char __user *buf, size_t count,
                 }
 
                 n = min_t(u64, remaining, sectors_read*dev->blk_size-offset);
+                src = dev->bounce_buf+offset;
                 dev_dbg(&dev->sbd.core,
-                        "%s:%u: copy %lu bytes from 0x%p to user 0x%p\n",
-                        __func__, __LINE__, n, dev->bounce_buf+offset, buf);
-                if (copy_to_user(buf, dev->bounce_buf+offset, n)) {
-                        mutex_unlock(&priv->mutex);
-                        sectors_read = -EFAULT;
-                        goto fail;
+                        "%s:%u: copy %lu bytes from 0x%p to U0x%p/K0x%p\n",
+                        __func__, __LINE__, n, src, userbuf, kernelbuf);
+                if (userbuf) {
+                        if (copy_to_user(userbuf, src, n)) {
+                                mutex_unlock(&priv->mutex);
+                                sectors_read = -EFAULT;
+                                goto fail;
+                        }
+                        userbuf += n;
+                }
+                if (kernelbuf) {
+                        memcpy(kernelbuf, src, n);
+                        kernelbuf += n;
                 }
 
                 mutex_unlock(&priv->mutex);
 
                 *pos += n;
-                buf += n;
                 remaining -= n;
                 start_sector += sectors_read;
                 offset = 0;
@@ -169,8 +177,8 @@ fail:
         return sectors_read;
 }
 
-static ssize_t ps3flash_write(struct file *file, const char __user *buf,
-                              size_t count, loff_t *pos)
+static ssize_t ps3flash_write(const char __user *userbuf,
+                              const void *kernelbuf, size_t count, loff_t *pos)
 {
         struct ps3_storage_device *dev = ps3flash_dev;
         struct ps3flash_private *priv = ps3_system_bus_get_drvdata(&dev->sbd);
@@ -179,10 +187,11 @@ static ssize_t ps3flash_write(struct file *file, const char __user *buf,
         ssize_t res;
         size_t remaining, n;
         unsigned int sec_off;
+        void *dst;
 
         dev_dbg(&dev->sbd.core,
-                "%s:%u: Writing %zu bytes at position %lld from user 0x%p\n",
-                __func__, __LINE__, count, *pos, buf);
+                "%s:%u: Writing %zu bytes at position %lld from U0x%p/K0x%p\n",
+                __func__, __LINE__, count, *pos, userbuf, kernelbuf);
 
         size = dev->regions[dev->region_idx].size*dev->blk_size;
         if (*pos >= size || !count)
@@ -259,12 +268,20 @@ static ssize_t ps3flash_write(struct file *file, const char __user *buf,
                 }
 
                 n = min_t(u64, remaining, dev->bounce_size-offset);
+                dst = dev->bounce_buf+offset;
                 dev_dbg(&dev->sbd.core,
-                        "%s:%u: copy %lu bytes from user 0x%p to 0x%p\n",
-                        __func__, __LINE__, n, buf, dev->bounce_buf+offset);
-                if (copy_from_user(dev->bounce_buf+offset, buf, n)) {
-                        res = -EFAULT;
-                        goto fail;
+                        "%s:%u: copy %lu bytes from U0x%p/K0x%p to 0x%p\n",
+                        __func__, __LINE__, n, userbuf, kernelbuf, dst);
+                if (userbuf) {
+                        if (copy_from_user(dst, userbuf, n)) {
+                                res = -EFAULT;
+                                goto fail;
+                        }
+                        userbuf += n;
+                }
+                if (kernelbuf) {
+                        memcpy(dst, kernelbuf, n);
+                        kernelbuf += n;
                 }
 
                 res = ps3flash_write_chunk(dev, start_write_sector);
@@ -274,7 +291,6 @@ static ssize_t ps3flash_write(struct file *file, const char __user *buf,
                 mutex_unlock(&priv->mutex);
 
                 *pos += n;
-                buf += n;
                 remaining -= n;
                 start_write_sector += chunk_sectors;
                 head = 0;
@@ -288,6 +304,29 @@ fail:
         return res;
 }
 
+static ssize_t ps3flash_user_read(struct file *file, char __user *buf,
+                                  size_t count, loff_t *pos)
+{
+        return ps3flash_read(buf, NULL, count, pos);
+}
+
+static ssize_t ps3flash_user_write(struct file *file, const char __user *buf,
+                                   size_t count, loff_t *pos)
+{
+        return ps3flash_write(buf, NULL, count, pos);
+}
+
+static ssize_t ps3flash_kernel_read(void *buf, size_t count, loff_t pos)
+{
+        return ps3flash_read(NULL, buf, count, &pos);
+}
+
+static ssize_t ps3flash_kernel_write(const void *buf, size_t count,
+                                     loff_t pos)
+{
+        return ps3flash_write(NULL, buf, count, &pos);
+}
+
 
 static irqreturn_t ps3flash_interrupt(int irq, void *data)
 {
@@ -312,12 +351,16 @@ static irqreturn_t ps3flash_interrupt(int irq, void *data)
         return IRQ_HANDLED;
 }
 
-
 static const struct file_operations ps3flash_fops = {
         .owner  = THIS_MODULE,
         .llseek = ps3flash_llseek,
-        .read   = ps3flash_read,
-        .write  = ps3flash_write,
+        .read   = ps3flash_user_read,
+        .write  = ps3flash_user_write,
+};
+
+static const struct ps3_os_area_flash_ops ps3flash_kernel_ops = {
+        .read   = ps3flash_kernel_read,
+        .write  = ps3flash_kernel_write,
 };
 
 static struct miscdevice ps3flash_misc = {
@@ -386,6 +429,8 @@ static int __devinit ps3flash_probe(struct ps3_system_bus_device *_dev)
 
         dev_info(&dev->sbd.core, "%s:%u: registered misc device %d\n",
                  __func__, __LINE__, ps3flash_misc.minor);
+
+        ps3_os_area_flash_register(&ps3flash_kernel_ops);
         return 0;
 
 fail_teardown:
@@ -402,6 +447,7 @@ static int ps3flash_remove(struct ps3_system_bus_device *_dev)
 {
         struct ps3_storage_device *dev = to_ps3_storage_device(&_dev->core);
 
+        ps3_os_area_flash_register(NULL);
         misc_deregister(&ps3flash_misc);
         ps3stor_teardown(dev);
         kfree(ps3_system_bus_get_drvdata(&dev->sbd));