+static void __init trim_pavail(unsigned long *cur_size_p,
+ unsigned long *end_of_phys_p)
+{
+ unsigned long to_trim = *cur_size_p - cmdline_memory_size;
+ unsigned long avoid_start, avoid_end;
+ int i;
+
+ to_trim = PAGE_ALIGN(to_trim);
+
+ avoid_start = avoid_end = 0;
+#ifdef CONFIG_BLK_DEV_INITRD
+ avoid_start = initrd_start;
+ avoid_end = PAGE_ALIGN(initrd_end);
+#endif
+
+ /* Trim some pavail[] entries in order to satisfy the
+ * requested "mem=xxx" kernel command line specification.
+ *
+ * We must not trim off the kernel image area nor the
+ * initial ramdisk range (if any). Also, we must not trim
+ * any pavail[] entry down to zero in order to preserve
+ * the invariant that all pavail[] entries have a non-zero
+ * size which is assumed by all of the code in here.
+ */
+ for (i = 0; i < pavail_ents; i++) {
+ unsigned long start, end, kern_end;
+ unsigned long trim_low, trim_high, n;
+
+ kern_end = PAGE_ALIGN(kern_base + kern_size);
+
+ trim_low = start = pavail[i].phys_addr;
+ trim_high = end = start + pavail[i].reg_size;
+
+ if (kern_base >= start &&
+ kern_base < end) {
+ trim_low = kern_base;
+ if (kern_end >= end)
+ continue;
+ }
+ if (kern_end >= start &&
+ kern_end < end) {
+ trim_high = kern_end;
+ }
+ if (avoid_start &&
+ avoid_start >= start &&
+ avoid_start < end) {
+ if (trim_low > avoid_start)
+ trim_low = avoid_start;
+ if (avoid_end >= end)
+ continue;
+ }
+ if (avoid_end &&
+ avoid_end >= start &&
+ avoid_end < end) {
+ if (trim_high < avoid_end)
+ trim_high = avoid_end;
+ }
+
+ if (trim_high <= trim_low)
+ continue;
+
+ if (trim_low == start && trim_high == end) {
+ /* Whole chunk is available for trimming.
+ * Trim all except one page, in order to keep
+ * entry non-empty.
+ */
+ n = (end - start) - PAGE_SIZE;
+ if (n > to_trim)
+ n = to_trim;
+
+ if (n) {
+ pavail[i].phys_addr += n;
+ pavail[i].reg_size -= n;
+ to_trim -= n;
+ }
+ } else {
+ n = (trim_low - start);
+ if (n > to_trim)
+ n = to_trim;
+
+ if (n) {
+ pavail[i].phys_addr += n;
+ pavail[i].reg_size -= n;
+ to_trim -= n;
+ }
+ if (to_trim) {
+ n = end - trim_high;
+ if (n > to_trim)
+ n = to_trim;
+ if (n) {
+ pavail[i].reg_size -= n;
+ to_trim -= n;
+ }
+ }
+ }
+
+ if (!to_trim)
+ break;
+ }
+
+ /* Recalculate. */
+ *cur_size_p = 0UL;
+ for (i = 0; i < pavail_ents; i++) {
+ *end_of_phys_p = pavail[i].phys_addr +
+ pavail[i].reg_size;
+ *cur_size_p += pavail[i].reg_size;
+ }
+}
+