s390/hypfs: simplify memory allocation

Simplify memory allocation for diagnose 204 memory buffer:

- allocate with __vmalloc_node() to enure page alignment
- allocate real / physical memory area also within vmalloc area and handle
  vmalloc to real / physical address translation within diag204().
Acked-by: Alexander Gordeev <agordeev@linux.ibm.com>
Reviewed-by: Mete Durlu <meted@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>

arch/s390/hypfs/hypfs_diag.c

@@ -29,7 +29,6 @@ static enum diag204_sc diag204_store_sc;	/* used subcode for store */
 static enum diag204_format diag204_info_type;	/* used diag 204 data format */
 
 static void *diag204_buf;		/* 4K aligned buffer for diag204 data */
-static void *diag204_buf_vmalloc;	/* vmalloc pointer for diag204 data */
 static int diag204_buf_pages;		/* number of pages for diag204 data */
 
 static struct dentry *dbfs_d204_file;
@@ -212,14 +211,7 @@ static inline __u64 phys_cpu__ctidx(enum diag204_format type, void *hdr)
 
 static void diag204_free_buffer(void)
 {
-	if (!diag204_buf)
-		return;
-	if (diag204_buf_vmalloc) {
-		vfree(diag204_buf_vmalloc);
-		diag204_buf_vmalloc = NULL;
-	} else {
-		free_pages((unsigned long) diag204_buf, 0);
-	}
+	vfree(diag204_buf);
 	diag204_buf = NULL;
 }
 
@@ -228,26 +220,6 @@ static void *page_align_ptr(void *ptr)
 	return (void *) PAGE_ALIGN((unsigned long) ptr);
 }
 
-static void *diag204_alloc_vbuf(int pages)
-{
-	/* The buffer has to be page aligned! */
-	diag204_buf_vmalloc = vmalloc(array_size(PAGE_SIZE, (pages + 1)));
-	if (!diag204_buf_vmalloc)
-		return ERR_PTR(-ENOMEM);
-	diag204_buf = page_align_ptr(diag204_buf_vmalloc);
-	diag204_buf_pages = pages;
-	return diag204_buf;
-}
-
-static void *diag204_alloc_rbuf(void)
-{
-	diag204_buf = (void*)__get_free_pages(GFP_KERNEL,0);
-	if (!diag204_buf)
-		return ERR_PTR(-ENOMEM);
-	diag204_buf_pages = 1;
-	return diag204_buf;
-}
-
 static void *diag204_get_buffer(enum diag204_format fmt, int *pages)
 {
 	if (diag204_buf) {
@@ -256,15 +228,19 @@ static void *diag204_get_buffer(enum diag204_format fmt, int *pages)
 	}
 	if (fmt == DIAG204_INFO_SIMPLE) {
 		*pages = 1;
-		return diag204_alloc_rbuf();
 	} else {/* DIAG204_INFO_EXT */
 		*pages = diag204((unsigned long)DIAG204_SUBC_RSI |
 				 (unsigned long)DIAG204_INFO_EXT, 0, NULL);
 		if (*pages <= 0)
 			return ERR_PTR(-ENOSYS);
-		else
-			return diag204_alloc_vbuf(*pages);
 	}
+	diag204_buf = __vmalloc_node(array_size(*pages, PAGE_SIZE),
+				     PAGE_SIZE, GFP_KERNEL, NUMA_NO_NODE,
+				     __builtin_return_address(0));
+	if (!diag204_buf)
+		return ERR_PTR(-ENOMEM);
+	diag204_buf_pages = *pages;
+	return diag204_buf;
 }
 
 /*

arch/s390/kernel/diag.c

@@ -11,6 +11,7 @@
 #include <linux/cpu.h>
 #include <linux/seq_file.h>
 #include <linux/debugfs.h>
+#include <linux/vmalloc.h>
 #include <asm/asm-extable.h>
 #include <asm/diag.h>
 #include <asm/trace/diag.h>
@@ -168,11 +169,30 @@ static inline int __diag204(unsigned long *subcode, unsigned long size, void *ad
 	return rp.odd;
 }
 
+/**
+ * diag204() - Issue diagnose 204 call.
+ * @subcode: Subcode of diagnose 204 to be executed.
+ * @size: Size of area in pages which @area points to, if given.
+ * @addr: Vmalloc'ed memory area where the result is written to.
+ *
+ * Execute diagnose 204 with the given subcode and write the result to the
+ * memory area specified with @addr. For subcodes which do not write a
+ * result to memory both @size and @addr must be zero. If @addr is
+ * specified it must be page aligned and must have been allocated with
+ * vmalloc(). Conversion to real / physical addresses will be handled by
+ * this function if required.
+ */
 int diag204(unsigned long subcode, unsigned long size, void *addr)
 {
-	diag_stat_inc(DIAG_STAT_X204);
+	if (addr) {
+		if (WARN_ON_ONCE(!is_vmalloc_addr(addr)))
+			return -1;
+		if (WARN_ON_ONCE(!IS_ALIGNED((unsigned long)addr, PAGE_SIZE)))
+			return -1;
+	}
 	if ((subcode & DIAG204_SUBCODE_MASK) == DIAG204_SUBC_STIB4)
-		addr = (void *)__pa(addr);
+		addr = (void *)pfn_to_phys(vmalloc_to_pfn(addr));
+	diag_stat_inc(DIAG_STAT_X204);
 	size = __diag204(&subcode, size, addr);
 	if (subcode)
 		return -1;