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Commit 44e5ddc4e9d52cd5eeda42bb7518b306beab24ee

Authored by Michael Holzheu
Committed by Martin Schwidefsky
1 parent c86cce2a20
Exists in master and in 6 other branches imx_3.10.17_1.0.1_ga, imx_3.10.53_1.1.0_ga, imx_3.14.28_1.0.0_ga, smarc-imx_3.10.53_1.1.0_ga, smarc-imx_3.14.28_1.0.0_ga, smarc-l5.0.0_1.0.0-ga

[S390] Rework create_mem_hole() function 

This patch makes the create_mem_hole() function more readable and
fixes some minor bugs (e.g. off-by-one problems).

Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

Showing 1 changed file with 67 additions and 55 deletions Side-by-side Diff

arch/s390/kernel/mem_detect.c
Diff comments   View file @ 44e5ddc
... ... @@ -64,70 +64,82 @@
64 64 EXPORT_SYMBOL(detect_memory_layout);
65 65  
66 66 /*
  67 + * Move memory chunks array from index "from" to index "to"
  68 + */
  69 +static void mem_chunk_move(struct mem_chunk chunk[], int to, int from)
  70 +{
  71 + int cnt = MEMORY_CHUNKS - to;
  72 +
  73 + memmove(&chunk[to], &chunk[from], cnt * sizeof(struct mem_chunk));
  74 +}
  75 +
  76 +/*
  77 + * Initialize memory chunk
  78 + */
  79 +static void mem_chunk_init(struct mem_chunk *chunk, unsigned long addr,
  80 + unsigned long size, int type)
  81 +{
  82 + chunk->type = type;
  83 + chunk->addr = addr;
  84 + chunk->size = size;
  85 +}
  86 +
  87 +/*
67 88 * Create memory hole with given address, size, and type
68 89 */
69   -void create_mem_hole(struct mem_chunk chunks[], unsigned long addr,
  90 +void create_mem_hole(struct mem_chunk chunk[], unsigned long addr,
70 91 unsigned long size, int type)
71 92 {
72   - unsigned long start, end, new_size;
73   - int i;
  93 + unsigned long lh_start, lh_end, lh_size, ch_start, ch_end, ch_size;
  94 + int i, ch_type;
74 95  
75 96 for (i = 0; i < MEMORY_CHUNKS; i++) {
76   - if (chunks[i].size == 0)
  97 + if (chunk[i].size == 0)
77 98 continue;
78   - if (addr + size < chunks[i].addr)
79   - continue;
80   - if (addr >= chunks[i].addr + chunks[i].size)
81   - continue;
82   - start = max(addr, chunks[i].addr);
83   - end = min(addr + size, chunks[i].addr + chunks[i].size);
84   - new_size = end - start;
85   - if (new_size == 0)
86   - continue;
87   - if (start == chunks[i].addr &&
88   - end == chunks[i].addr + chunks[i].size) {
89   - /* Remove chunk */
90   - chunks[i].type = type;
91   - } else if (start == chunks[i].addr) {
92   - /* Make chunk smaller at start */
93   - if (i >= MEMORY_CHUNKS - 1)
94   - panic("Unable to create memory hole");
95   - memmove(&chunks[i + 1], &chunks[i],
96   - sizeof(struct mem_chunk) *
97   - (MEMORY_CHUNKS - (i + 1)));
98   - chunks[i + 1].addr = chunks[i].addr + new_size;
99   - chunks[i + 1].size = chunks[i].size - new_size;
100   - chunks[i].size = new_size;
101   - chunks[i].type = type;
  99 +
  100 + /* Define chunk properties */
  101 + ch_start = chunk[i].addr;
  102 + ch_size = chunk[i].size;
  103 + ch_end = ch_start + ch_size - 1;
  104 + ch_type = chunk[i].type;
  105 +
  106 + /* Is memory chunk hit by memory hole? */
  107 + if (addr + size <= ch_start)
  108 + continue; /* No: memory hole in front of chunk */
  109 + if (addr > ch_end)
  110 + continue; /* No: memory hole after chunk */
  111 +
  112 + /* Yes: Define local hole properties */
  113 + lh_start = max(addr, chunk[i].addr);
  114 + lh_end = min(addr + size - 1, ch_end);
  115 + lh_size = lh_end - lh_start + 1;
  116 +
  117 + if (lh_start == ch_start && lh_end == ch_end) {
  118 + /* Hole covers complete memory chunk */
  119 + mem_chunk_init(&chunk[i], lh_start, lh_size, type);
  120 + } else if (lh_end == ch_end) {
  121 + /* Hole starts in memory chunk and convers chunk end */
  122 + mem_chunk_move(chunk, i + 1, i);
  123 + mem_chunk_init(&chunk[i], ch_start, ch_size - lh_size,
  124 + ch_type);
  125 + mem_chunk_init(&chunk[i + 1], lh_start, lh_size, type);
102 126 i += 1;
103   - } else if (end == chunks[i].addr + chunks[i].size) {
104   - /* Make chunk smaller at end */
105   - if (i >= MEMORY_CHUNKS - 1)
106   - panic("Unable to create memory hole");
107   - memmove(&chunks[i + 1], &chunks[i],
108   - sizeof(struct mem_chunk) *
109   - (MEMORY_CHUNKS - (i + 1)));
110   - chunks[i + 1].addr = start;
111   - chunks[i + 1].size = new_size;
112   - chunks[i + 1].type = type;
113   - chunks[i].size -= new_size;
114   - i += 1;
  127 + } else if (lh_start == ch_start) {
  128 + /* Hole ends in memory chunk */
  129 + mem_chunk_move(chunk, i + 1, i);
  130 + mem_chunk_init(&chunk[i], lh_start, lh_size, type);
  131 + mem_chunk_init(&chunk[i + 1], lh_end + 1,
  132 + ch_size - lh_size, ch_type);
  133 + break;
115 134 } else {
116   - /* Create memory hole */
117   - if (i >= MEMORY_CHUNKS - 2)
118   - panic("Unable to create memory hole");
119   - memmove(&chunks[i + 2], &chunks[i],
120   - sizeof(struct mem_chunk) *
121   - (MEMORY_CHUNKS - (i + 2)));
122   - chunks[i + 1].addr = addr;
123   - chunks[i + 1].size = size;
124   - chunks[i + 1].type = type;
125   - chunks[i + 2].addr = addr + size;
126   - chunks[i + 2].size =
127   - chunks[i].addr + chunks[i].size - (addr + size);
128   - chunks[i + 2].type = chunks[i].type;
129   - chunks[i].size = addr - chunks[i].addr;
130   - i += 2;
  135 + /* Hole splits memory chunk */
  136 + mem_chunk_move(chunk, i + 2, i);
  137 + mem_chunk_init(&chunk[i], ch_start,
  138 + lh_start - ch_start, ch_type);
  139 + mem_chunk_init(&chunk[i + 1], lh_start, lh_size, type);
  140 + mem_chunk_init(&chunk[i + 2], lh_end + 1,
  141 + ch_end - lh_end, ch_type);
  142 + break;
131 143 }
132 144 }
133 145 }