vmcore: convert read_from_oldmem() to take an iov_iter

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

Link: https://lkml.kernel.org/r/20220408090636.560886-4-bhe@redhat.com
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Baoquan He <bhe@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Tiezhu Yang <yangtiezhu@loongson.cn>
Cc: Amit Daniel Kachhap <amit.kachhap@arm.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/arch/x86/kernel/crash_dump_64.c b/arch/x86/kernel/crash_dump_64.c
index 94fe4af..e75bc2f 100644 (file)
--- a/arch/x86/kernel/crash_dump_64.c
+++ b/arch/x86/kernel/crash_dump_64.c
@@ -54,6 +54,11 @@ 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 4a72186..4eaeb64 100644 (file)
--- a/fs/proc/vmcore.c
+++ b/fs/proc/vmcore.c
@@ -129,7 +129,7 @@ static int open_vmcore(struct inode *inode, struct file *file)
 }
 
 /* Reads a page from the oldmem device from given offset. */
-static 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;
@@ -178,27 +178,6 @@ static 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
  */
@@ -218,7 +197,12 @@ 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);
 }
 
 /*
@@ -226,7 +210,13 @@ 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));
 }
 
 /*
@@ -402,7 +392,7 @@ static ssize_t __read_vmcore(struct iov_iter *iter, loff_t *fpos)
                                            m->offset + m->size - *fpos,
                                            iov_iter_count(iter));
                        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 a1cf7d5..0f3a656 100644 (file)
--- 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;
 }