Merge tag 'io_uring-6.5-2023-07-21' of git://git.kernel.dk/linux

[sfrench/cifs-2.6.git] / arch / parisc / kernel / sys_parisc.c

diff --git a/arch/parisc/kernel/sys_parisc.c b/arch/parisc/kernel/sys_parisc.c
index 9915062d5243c38776dcb2296faa9165e32d55bd..ca2d537e25b1872ab15126c28aa892a13b2ca0ed 100644 (file)
--- a/arch/parisc/kernel/sys_parisc.c
+++ b/arch/parisc/kernel/sys_parisc.c
@@ -27,12 +27,17 @@
 #include <linux/elf-randomize.h>
 
 /*
- * Construct an artificial page offset for the mapping based on the physical
+ * Construct an artificial page offset for the mapping based on the virtual
  * address of the kernel file mapping variable.
+ * If filp is zero the calculated pgoff value aliases the memory of the given
+ * address. This is useful for io_uring where the mapping shall alias a kernel
+ * address and a userspace adress where both the kernel and the userspace
+ * access the same memory region.
  */
-#define GET_FILP_PGOFF(filp)           \
-       (filp ? (((unsigned long) filp->f_mapping) >> 8)        \
-                & ((SHM_COLOUR-1) >> PAGE_SHIFT) : 0UL)
+#define GET_FILP_PGOFF(filp, addr)             \
+       ((filp ? (((unsigned long) filp->f_mapping) >> 8)       \
+                & ((SHM_COLOUR-1) >> PAGE_SHIFT) : 0UL)        \
+         + (addr >> PAGE_SHIFT))
 
 static unsigned long shared_align_offset(unsigned long filp_pgoff,
                                         unsigned long pgoff)
@@ -112,7 +117,7 @@ static unsigned long arch_get_unmapped_area_common(struct file *filp,
        do_color_align = 0;
        if (filp || (flags & MAP_SHARED))
                do_color_align = 1;
-       filp_pgoff = GET_FILP_PGOFF(filp);
+       filp_pgoff = GET_FILP_PGOFF(filp, addr);
 
        if (flags & MAP_FIXED) {
                /* Even MAP_FIXED mappings must reside within TASK_SIZE */