[PATCH 3/3] vmcore: Convert read_from_oldmem() to take an iov_iter

Matthew Wilcox (Oracle)
2021-12-13T00:06:50Z

Remove the read_from_oldmem() wrapper introduced earlier and convert
all the remaining callers to pass an iov_iter.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
arch/x86/kernel/crash_dump_64.c | 7 +++++-
fs/proc/vmcore.c | 40 +++++++++++++--------------------
include/linux/crash_dump.h | 10 ++++-----
3 files changed, 25 insertions(+), 32 deletions(-)

diff --git a/arch/x86/kernel/crash_dump_64.c b/arch/x86/kernel/crash_dump_64.c
index 8d91e5f2e14d..991e09b80852 100644
--- a/arch/x86/kernel/crash_dump_64.c
+++ b/arch/x86/kernel/crash_dump_64.c
@@ -68,6 +68,11 @@ ssize_t copy_oldmem_page_encrypted(struct iov_iter *iter, unsigned long pfn,

ssize_t elfcorehdr_read(char *buf, size_t count, u64 *ppos)
{
- return read_from_oldmem(buf, count, ppos, 0,
+ struct kvec kvec = { .iov_base = buf, .iov_len = count };
+ struct iov_iter iter;
+
+ iov_iter_kvec(&iter, READ, &kvec, 1, count);
+
+ return read_from_oldmem(&iter, count, ppos,
cc_platform_has(CC_ATTR_GUEST_MEM_ENCRYPT));
}
diff --git a/fs/proc/vmcore.c b/fs/proc/vmcore.c
index 443cbaf16ec8..986474f02a02 100644
--- a/fs/proc/vmcore.c
+++ b/fs/proc/vmcore.c
@@ -132,7 +132,7 @@ static int open_vmcore(struct inode *inode, struct file *file)
}

/* Reads a page from the oldmem device from given offset. */
-ssize_t read_from_oldmem_iter(struct iov_iter *iter, size_t count,
+ssize_t read_from_oldmem(struct iov_iter *iter, size_t count,
u64 *ppos, bool encrypted)
{
unsigned long pfn, offset;
@@ -180,27 +180,6 @@ ssize_t read_from_oldmem_iter(struct iov_iter *iter, size_t count,
return read;
}

-ssize_t read_from_oldmem(char *buf, size_t count,
- u64 *ppos, int userbuf,
- bool encrypted)
-{
- struct iov_iter iter;
- struct iovec iov;
- struct kvec kvec;
-
- if (userbuf) {
- iov.iov_base = (__force void __user *)buf;
- iov.iov_len = count;
- iov_iter_init(&iter, READ, &iov, 1, count);
- } else {
- kvec.iov_base = buf;
- kvec.iov_len = count;
- iov_iter_kvec(&iter, READ, &kvec, 1, count);
- }
-
- return read_from_oldmem_iter(&iter, count, ppos, encrypted);
-}
-
/*
* Architectures may override this function to allocate ELF header in 2nd kernel
*/
@@ -220,7 +199,12 @@ void __weak elfcorehdr_free(unsigned long long addr)
*/
ssize_t __weak elfcorehdr_read(char *buf, size_t count, u64 *ppos)
{
- return read_from_oldmem(buf, count, ppos, 0, false);
+ struct kvec kvec = { .iov_base = buf, .iov_len = count };
+ struct iov_iter iter;
+
+ iov_iter_kvec(&iter, READ, &kvec, 1, count);
+
+ return read_from_oldmem(&iter, count, ppos, false);
}

/*
@@ -228,7 +212,13 @@ ssize_t __weak elfcorehdr_read(char *buf, size_t count, u64 *ppos)
*/
ssize_t __weak elfcorehdr_read_notes(char *buf, size_t count, u64 *ppos)
{
- return read_from_oldmem(buf, count, ppos, 0, cc_platform_has(CC_ATTR_MEM_ENCRYPT));
+ struct kvec kvec = { .iov_base = buf, .iov_len = count };
+ struct iov_iter iter;
+
+ iov_iter_kvec(&iter, READ, &kvec, 1, count);
+
+ return read_from_oldmem(&iter, count, ppos,
+ cc_platform_has(CC_ATTR_MEM_ENCRYPT));
}

/*
@@ -405,7 +395,7 @@ static ssize_t __read_vmcore(struct iov_iter *iter, loff_t *fpos)
m->offset + m->size - *fpos,
iter->count);
start = m->paddr + *fpos - m->offset;
- tmp = read_from_oldmem_iter(iter, tsz, &start,
+ tmp = read_from_oldmem(iter, tsz, &start,
cc_platform_has(CC_ATTR_MEM_ENCRYPT));
if (tmp < 0)
return tmp;
diff --git a/include/linux/crash_dump.h b/include/linux/crash_dump.h
index a1cf7d5c03c7..0f3a656293b0 100644
--- a/include/linux/crash_dump.h
+++ b/include/linux/crash_dump.h
@@ -134,13 +134,11 @@ static inline int vmcore_add_device_dump(struct vmcoredd_data *data)
#endif /* CONFIG_PROC_VMCORE_DEVICE_DUMP */

#ifdef CONFIG_PROC_VMCORE
-ssize_t read_from_oldmem(char *buf, size_t count,
- u64 *ppos, int userbuf,
- bool encrypted);
+ssize_t read_from_oldmem(struct iov_iter *iter, size_t count,
+ u64 *ppos, bool encrypted);
#else
-static inline ssize_t read_from_oldmem(char *buf, size_t count,
- u64 *ppos, int userbuf,
- bool encrypted)
+static inline ssize_t read_from_oldmem(struct iov_iter *iter, size_t count,
+ u64 *ppos, bool encrypted)
{
return -EOPNOTSUPP;
}
--
2.33.0