* [PATCH 1/4] iov_iter: Provide copy_iomem_to|from_iter()
2024-11-07 16:34 [PATCH 0/4] Add iomem helpers for use from debugfs Michal Wajdeczko
@ 2024-11-07 16:34 ` Michal Wajdeczko
2024-11-07 20:13 ` Matthew Wilcox
2024-11-07 16:34 ` [PATCH 2/4] libfs: Provide simple_read_from|write_to_iomem() Michal Wajdeczko
1 sibling, 1 reply; 4+ messages in thread
From: Michal Wajdeczko @ 2024-11-07 16:34 UTC (permalink / raw)
To: intel-xe
Cc: Michal Wajdeczko, Alexander Viro, Andrew Morton, Matthew Wilcox,
Rodrigo Vivi, Matthew Brost, linux-kernel, linux-fsdevel
Define simple copy helpers that work on I/O memory. This will
allow reuse of existing framework functions in new use cases.
Signed-off-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
---
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Matthew Brost <matthew.brost@intel.com>
Cc: linux-kernel@vger.kernel.org
Cc: linux-fsdevel@vger.kernel.org
---
include/linux/uio.h | 4 ++++
lib/iov_iter.c | 42 ++++++++++++++++++++++++++++++++++++++++++
2 files changed, 46 insertions(+)
diff --git a/include/linux/uio.h b/include/linux/uio.h
index 853f9de5aa05..6d2a24293bd1 100644
--- a/include/linux/uio.h
+++ b/include/linux/uio.h
@@ -178,6 +178,10 @@ size_t copy_page_to_iter(struct page *page, size_t offset, size_t bytes,
struct iov_iter *i);
size_t copy_page_from_iter(struct page *page, size_t offset, size_t bytes,
struct iov_iter *i);
+size_t copy_iomem_to_iter(const void __iomem *from, size_t offset,
+ size_t bytes, struct iov_iter *i);
+size_t copy_iomem_from_iter(void __iomem *to, size_t offset,
+ size_t bytes, struct iov_iter *i);
size_t _copy_to_iter(const void *addr, size_t bytes, struct iov_iter *i);
size_t _copy_from_iter(void *addr, size_t bytes, struct iov_iter *i);
diff --git a/lib/iov_iter.c b/lib/iov_iter.c
index 908e75a28d90..e8c1f1c68716 100644
--- a/lib/iov_iter.c
+++ b/lib/iov_iter.c
@@ -435,6 +435,48 @@ size_t copy_page_from_iter(struct page *page, size_t offset, size_t bytes,
}
EXPORT_SYMBOL(copy_page_from_iter);
+size_t copy_iomem_to_iter(const void __iomem *from, size_t offset,
+ size_t bytes, struct iov_iter *i)
+{
+ unsigned char buf[SMP_CACHE_BYTES];
+ size_t progress = 0, copied, len;
+
+ from += offset;
+ while (bytes) {
+ len = min(bytes, sizeof(buf));
+ memcpy_fromio(buf, from + progress, len);
+ copied = _copy_to_iter(buf, len, i);
+ if (!copied)
+ break;
+ bytes -= copied;
+ progress += copied;
+ }
+
+ return progress;
+}
+EXPORT_SYMBOL(copy_iomem_to_iter);
+
+size_t copy_iomem_from_iter(void __iomem *to, size_t offset,
+ size_t bytes, struct iov_iter *i)
+{
+ unsigned char buf[SMP_CACHE_BYTES];
+ size_t progress = 0, copied, len;
+
+ to += offset;
+ while (bytes) {
+ len = min(bytes, sizeof(buf));
+ copied = _copy_from_iter(buf, len, i);
+ if (!copied)
+ break;
+ memcpy_toio(to + progress, buf, copied);
+ bytes -= copied;
+ progress += copied;
+ }
+
+ return progress;
+}
+EXPORT_SYMBOL(copy_iomem_from_iter);
+
static __always_inline
size_t zero_to_user_iter(void __user *iter_to, size_t progress,
size_t len, void *priv, void *priv2)
--
2.43.0
^ permalink raw reply [flat|nested] 4+ messages in thread* [PATCH 2/4] libfs: Provide simple_read_from|write_to_iomem()
2024-11-07 16:34 [PATCH 0/4] Add iomem helpers for use from debugfs Michal Wajdeczko
2024-11-07 16:34 ` [PATCH 1/4] iov_iter: Provide copy_iomem_to|from_iter() Michal Wajdeczko
@ 2024-11-07 16:34 ` Michal Wajdeczko
1 sibling, 0 replies; 4+ messages in thread
From: Michal Wajdeczko @ 2024-11-07 16:34 UTC (permalink / raw)
To: intel-xe
Cc: Michal Wajdeczko, Alexander Viro, Christian Brauner, Jan Kara,
Rodrigo Vivi, Matthew Brost, linux-fsdevel, linux-kernel
New functions are similar to simple_read_from|write_to_buffer()
but work on the I/O memory instead. Will allow wider code reuse.
Signed-off-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
---
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Jan Kara <jack@suse.cz>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Matthew Brost <matthew.brost@intel.com>
Cc: linux-fsdevel@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
---
fs/libfs.c | 78 ++++++++++++++++++++++++++++++++++++++++++++++
include/linux/fs.h | 5 +++
2 files changed, 83 insertions(+)
diff --git a/fs/libfs.c b/fs/libfs.c
index 46966fd8bcf9..0e4f0d50d4f3 100644
--- a/fs/libfs.c
+++ b/fs/libfs.c
@@ -1095,6 +1095,84 @@ void simple_release_fs(struct vfsmount **mount, int *count)
}
EXPORT_SYMBOL(simple_release_fs);
+/**
+ * simple_read_from_iomem() - copy data from the I/O memory to user space
+ * @to: the user space buffer to read to
+ * @count: the maximum number of bytes to read
+ * @ppos: the current position in the buffer
+ * @from: the I/O memory to read from
+ * @available: the size of the iomem memory
+ *
+ * The simple_read_from_iomem() function reads up to @count bytes from the
+ * I/O memory @from at offset @ppos into the user space address starting at @to.
+ *
+ * Return: On success, the number of bytes read is returned and the offset
+ * @ppos is advanced by this number, or negative value is returned on error.
+ */
+ssize_t simple_read_from_iomem(void __user *to, size_t count, loff_t *ppos,
+ const void __iomem *from, size_t available)
+{
+ struct iov_iter iter;
+ loff_t pos = *ppos;
+ size_t copied;
+
+ if (pos < 0)
+ return -EINVAL;
+ if (pos >= available || !count)
+ return 0;
+ if (count > available - pos)
+ count = available - pos;
+ if (import_ubuf(ITER_DEST, to, count, &iter))
+ return -EFAULT;
+
+ copied = copy_iomem_to_iter(from, pos, count, &iter);
+ if (!copied)
+ return -EFAULT;
+
+ *ppos = pos + copied;
+ return copied;
+}
+EXPORT_SYMBOL(simple_read_from_iomem);
+
+/**
+ * simple_write_to_iomem() - copy data from user space to the I/O memory
+ * @to: the I/O memory to write to
+ * @available: the size of the I/O memory
+ * @ppos: the current position in the buffer
+ * @from: the user space buffer to read from
+ * @count: the maximum number of bytes to read
+ *
+ * The simple_write_to_iomem() function reads up to @count bytes from the user
+ * space address starting at @from into the I/O memory @to at offset @ppos.
+ *
+ * Return: On success, the number of bytes written is returned and the offset
+ * @ppos is advanced by this number, or negative value is returned on error.
+ */
+ssize_t simple_write_to_iomem(void __iomem *to, size_t available, loff_t *ppos,
+ const void __user *from, size_t count)
+{
+ struct iov_iter iter;
+ loff_t pos = *ppos;
+ size_t copied;
+
+ if (pos < 0)
+ return -EINVAL;
+ if (pos >= available || !count)
+ return 0;
+ if (count > available - pos)
+ count = available - pos;
+ if (import_ubuf(ITER_SOURCE, (void __user *)from, count, &iter))
+ return -EFAULT;
+
+ copied = copy_iomem_from_iter(to, pos, count, &iter);
+ if (!copied)
+ return -EFAULT;
+
+ *ppos = pos + copied;
+ return copied;
+}
+EXPORT_SYMBOL(simple_write_to_iomem);
+
/**
* simple_read_from_buffer - copy data from the buffer to user space
* @to: the user space buffer to read to
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 3559446279c1..2cc73c5961b0 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -3426,6 +3426,11 @@ extern ssize_t simple_read_from_buffer(void __user *to, size_t count,
extern ssize_t simple_write_to_buffer(void *to, size_t available, loff_t *ppos,
const void __user *from, size_t count);
+ssize_t simple_read_from_iomem(void __user *to, size_t count, loff_t *ppos,
+ const void __iomem *from, size_t available);
+ssize_t simple_write_to_iomem(void __iomem *to, size_t available, loff_t *ppos,
+ const void __user *from, size_t count);
+
struct offset_ctx {
struct maple_tree mt;
unsigned long next_offset;
--
2.43.0
^ permalink raw reply [flat|nested] 4+ messages in thread